Case Study

You opened the classroom door, breathing heavily and apologizing before your feet had even crossed the threshold. Dozens of heads turned in your direction, including the teacher's, whose annoyed gaze filtered through the reflection in his glasses.

Trying to catch your breath, you approached his desk and handed over the medical certificate, a simple check-up that unfortunately took longer than expected.

“You’re late,” the professor said sternly, examining the document exhaustively. “Take a seat, but don’t let this happen again.”

You nodded, feeling a bit more relieved, and walked towards your usual spot, moving down the central corridor under the curious gaze of your classmates.

When you finally sat down, Mina Myoui, the girl who sat right next to you in class, looked up from her immaculate notes and gave you a small, almost imperceptible, but comforting smile.

Mina was the kind of girl anyone would want next to them in class. Quiet, reserved, and absurdly intelligent. Even though your interactions were mostly limited to borrowing something the other needed or sharing the results of a previous assignment, you still got along well with her. She exuded a peacefulness that was always pleasant.

However, the peace lasted exactly three seconds. The professor banged on the table to get everyone's attention.

“Okay, as I just explained before this interruption, the next research project will be done in groups of four.” The professor looked directly at you. “You’ll have to join the only group of three left. The one with Misses Myoui, Hirai, and Minatozaki… Momo, are you eating in my class?”

Your brain froze for a moment. You slowly turned your head toward the back rows of the classroom.

There they were, sitting together, watching you with completely opposite reactions, the dynamic duo of faculty chaos: Momo Hirai and Sana Minatozaki. Along with Mina, they formed an inseparable trio of friends, but academically they were like fire and ice.

Sana waved at you energetically, flashing a bright smile, completely oblivious to the serious atmosphere of the classroom. Beside her, Momo tried to hide the remains of the potato chips she'd been eating in her backpack, a guilty smile playing on her lips. Her eyes found yours, and she gave you a thumbs-up, though you could swear she had no idea what the assignment was about.

Their reputation on campus was notorious. It wasn't that they were mean girls, it's just that they tended to live in their own universe, a parallel dimension where attention deficit was the norm and comical situations seemed to haunt them like a curse. They were fun, likable, and yes, highly attractive, but if you could have voluntarily chosen a group to stake 40% of your final grade on, they'd be at the bottom of the list.

Mina, beside you, let out a soft sigh of resignation and looked at you with a mixture of sympathy and apology in her eyes, as if to say: “Welcome to my life.”

You sighed heavily and slumped back in your chair, notebook still open, though you weren't paying attention to anything related to the class anymore. You were going to have to deal with this somehow, while your grade, your sanity, and your heart rate depended on Mina's infinite patience and your prayers to the gods.

Days later, you realized that no deity had answered your prayers.

The lab was completely empty except for the four of you. There was an extreme smell of chemicals and various disinfectants, but what hung most in the air was your growing sense of despair.

On the table, the sheet of paper with the project guidelines and instructions remained blank after more than two hours. You read the proposed topic one more time:

Research topic: “Analysis of the physical and psychological responses of humans to a pleasant, external physical stimulus.”

“Let me see if I understand…” Momo broke the silence. She was sitting across from you on a high stool, swinging her legs forward and holding a lab thermometer in one hand. “We need to find a volunteer, put them in a giant test tube, and see if they survive a massage?”

“No, Momo. We don’t all fit in test tubes,” Sana replied with complete seriousness, while trying to build a tower out of three beakers. “Besides, it says ‘pleasant physical stimulation.’ What if we tickle their feet? That’s physical stimulation. And some people like it. It makes me laugh. Laughter equals happiness, happiness equals pleasant. Science.”

You rubbed your temples hard, feeling the onset of a migraine that would last for weeks. You turned your head to the right, desperately searching for an anchor of sanity. Mina. She stood there, with a pen between her fingers and her eyes fixed on the sheet of paper, analyzing the proposal with a frown.

“Just ignore them,” Mina advised softly, leaning slightly toward you. “Based on the bibliography the professor recommended, the psychological approach is easier to measure if we isolate the stimulus. We could structure the theoretical framework by measuring heart rate, skin conductance, and immediate verbal response.”

You breathed a sigh of relief. Bless Mina Myoui.

“What do you think?”

You nodded in agreement, bringing your notebook closer to hers to share your notes.

“It’s perfect. If we formulate a hypothesis based on the release of endorphins and dopamine, we would only have to design a simple experiment.”

She seemed to consider it for a second.

“The problem is the stimulus. It has to be something easy to replicate in a controlled environment, something harmless but that generates a clear and immediate response in the nervous system.”

You both stared at the paper, lost in thoughtful silence, trying to find a variable that fit.

“Ah, I’ve got it!” Sana’s voice cut through the air abruptly.

You looked up and saw her hand raised as if she were in the middle of a real class, her eyes shining with pure excitement at having had an idea.

“Come on, Sana, enlighten us.” You said, caught somewhere between curiosity and fear.

“What if the stimulus was a kiss?” she suggested, tilting her head with a radiant smile.

“A kiss?” You and Mina asked at the same time, quite confused.

“Yes. It’s something physical, it’s external, and it’s generally very pleasant. It meets all the project requirements.”

You thought about it for a moment, and surprisingly, it actually met all your expectations perfectly. Considering everything you could have hoped for, it wasn't a bad idea at all. Except for one small detail.

Momo, who was now playing with an eraser on her side of the table, stopped dead, her eyes widening as she processed the scant information she had received.

“But for the project we need real results, right? Field data. We should test it right now to see if it works.”

That was the only slight drawback you saw to the idea; it was as if Momo had read your mind. How were you going to test it?

Before anyone could argue or raise their voice in protest, Sana leaned over Momo, planting a loud kiss on one of her cheeks. Your eyes widened at this, and noticing how the laboratory had fallen completely silent.

Sana stepped back and looked at her friend with a tender smile on her lips.

“What did you feel?” she asked, like a scientist awaiting the results of her experiment. “Was there any stimulation?”

Momo blinked, completely expressionless, and shrugged.

“I’m so used to you kissing me all day long that this means nothing to me anymore. It’s pointless.”

Sana pouted, visibly disappointed.

“That’s sad… You’re right. The test subject can’t be immune to the stimulus.”

“The problem is that neither of you is a suitable subject for the experiment. You know each other too well.” Mina interjected, already blushing herself as she noticed the red creeping up your neck.

Sana paused for a moment, her gaze sweeping around the empty laboratory. Momo mirrored her gesture. And then, as if they had rehearsed it, they both fixed their eyes on a single object.

You.

Mina, noticing the path of their gazes, looked up from her notebook and looked at you too. In an instant, you found yourself under the scrutiny of three pairs of eyes.

“No. No, no, no. Absolutely not.” You refused immediately, pushing the stool back and raising your hands defensively.

You felt the heat rush up your chest, flooding your cheeks and turning your ears bright red. Your heart, which had been calm just moments before, began to pound against your ribs.

“It’s for the homework!” Sana insisted, gliding off her chair with feline agility. She began circling the table, closing the distance between you two with slow steps and a thoroughly mischievous smile.

“Sana, what are you doing? We’re at university!” you protested, in a louder voice than usual, pressing your back against the table immediately behind you as she leaned dangerously over you, invading your personal space with her sweet perfume.

“Mina, say something to her!”

But Mina just watched the scene with wide eyes, her hands clasped in her lap and a visible pink tint decorating her own cheeks, unable to stop the impending disaster.

“For forty percent of the grade…” Sana whispered, completely captivating you with her gaze as she moved closer to your face. “Sacrifices must be made.”

You closed your eyes tightly, waiting for the impact, your hands gripping the edges of the table as if you were about to fall off a cliff.

Mwah.

Sana's kiss landed squarely on your right cheek. It wasn't a timid touch; it was a firm, warm, and lingering kiss that left your skin burning. When you dared to open your eyes, Sana had only pulled back a few inches. She was staring at you, analyzing every millimeter of your face with a look of utter satisfaction.

“Wow!” she exclaimed, clapping her hands. “Immediate skin reaction: completely red cheeks. And you’re shivering a little. Momo, write that down!”

“Yes!” Momo snatched up the first pen she found and began to scribble in a corner of Mina’s notebook with comical seriousness.

"The guy... turns... red as a tomato." She muttered dictating her own writing.

“That’s not even scientific language!” you managed to say, though your voice came out choked. Your heart was racing, pounding in your chest so hard you were sure the three people present could hear it.

The butterflies in your stomach weren't flying, they were having a heavy metal concert.

“We need to compare the data.” Momo said suddenly, standing up with a strangely determined expression. “Sana is very noisy. My method will be more… controlled.”

Your eyes widened again. Wasn't she implying what you thought?

“Wait, Momo, no…” Before you could finish the sentence, Momo was already in front of you.

She gently held your shoulders, forcing you to look at her. Her face was millimeters from yours. You could see the subtle concentration in her eyes before she tilted her head and pressed her lips, this time, to your other cheek. Her kiss was very different: soft, and she took her time, leaving you completely petrified.

When she pulled away, she gave your cheek a quick, playful lick that left your brain completely short-circuiting. Two of the prettiest girls on campus had just kissed you in less than a minute, and your nervous system had completely shut down.

“Interesting…” Momo murmured, touching your neck with her fingertips. “His pulse is taking longer to return to normal with my stimulation. My kiss definitely had a deeper psychological impact.”

"That's cheating! Your kiss lasted longer!" Sana shouted, crossing her arms and pouting in annoyance.

They both turned slowly toward Mina, who had remained at the corner of the table, trying to shrink away to avoid being noticed. Her ears were so red they rivaled yours.

“Mina-chan…” Sana and Momo purred at the same time, with knowing glances.

“No, no, girls, I… I’m recording all the data.” Mina defended herself, clearing her throat and clutching her pen as if it were her last line of defense.

“Besides, someone has to maintain scientific objectivity.” She tried to excuse herself with a soft chuckle.

“But Mina, you’re the smartest of the group,” Sana said, affectionately putting an arm around Mina’s neck. “If you don’t participate, the scientific method isn’t valid. Right?” she asked, winking at you.

“We need all the samples we can get.” Momo agreed, moving away from you and giving her friend a slight nod.

You could only manage a groan of pure embarrassment, your head bowed. Mina looked at you. Seeing your utter vulnerability and the insistent pressure from her two friends, she sighed in surrender. She placed her pen on the table and stood up.

“I’m only… I’m only doing this for academic rigor,” she whispered.

She approached you with slow, elegant steps, and the laboratory seemed to fall silent. When she stopped right in front of you, you were forced to look up at her. Mina leaned toward you. Her shyness was almost palpable; she closed her eyes, and you could see the slight trembling of her eyelashes.

Unlike Sana and Momo's playful kisses, Mina's was a slow, exquisitely delicate touch, right at the corner of your lips. A contact so soft and warm that you felt an electric shock run down your spine. Your heart leaped wildly, and for a second you forgot how to breathe.

Mina slowly pulled away, opening her eyes with a shy gleam, and hurriedly returned to her seat, covering her mouth with one hand as she stared at her notes, completely embarrassed.

“That was a high-level stimulus! Look at those eyes!” Sana shouted, jumping for joy.

“Well, I guess we have everything now.” Momo said, and you felt a great relief throughout your body.

“Wait…” Mina interrupted, trying to regain her composure while avoiding eye contact.

"Scientifically speaking, the first round is not entirely conclusive."

"What do you mean it's not conclusive?!" You shrieked, flushing red with embarrassment.

“There was too much surprise. The subject wasn't prepared, so the adrenaline rush may have skewed the heart rate. We need to measure the response also with the subject aware of the preceding stimulus,” Mina explained, leaving you speechless.

Was this damned experiment never going to come to an end?

“Repeat round!” Sana exclaimed, clapping her hands.

By then, all you wanted was to leave that lab and cry. But deep down, you knew it was the best experience of your life.

“Furthermore, for the experiment to be rigorous, we need to test areas with a higher density of nerve receptors. The cheeks aren't enough.” Mina continued explaining, lowering her head to try and hide her even deeper blush.

"What do you mean by... NO!"

Sana turned to look at you, puckering her lips, mocking you.

"Have you ever kissed a girl before?" Momo teased, moving dangerously close to you.

“Of course, tons of them.” Tons? A lie as big as a skyscraper.

In the blink of an eye, Sana was on your left and Momo on your right. Momo moved closer and whispered just millimeters from your ear.

"And why do you look like you're about to melt?"

You didn't answer; the drops of cold sweat that gathered on your forehead were an answer in themselves.

Sana positioned herself in the center of your field of vision, still with that characteristic angelic smile of hers.

“Close your eyes.” She asked kindly. And you, tired of the arguments, followed her advice without offering any further resistance.

You tried to calm your own pulse and nervous system to finish as quickly as possible. For this second round, things were going to get more intense, and you needed 100% concentration and inner control if you didn't want to end up with another visit to the doctor.

You felt her breath close by, and to be honest, the anticipation was killing you. What you weren't prepared for was that instead of your cheek, her lips would fall against yours with deliberate intent.

You opened your eyes in shock, pale and frozen in place as Sana insistently moved her lips against yours. She pulled your arms around her waist and placed her own around your neck, gently embracing you and pressing herself against your body.

And for the first time, you let yourself go.

Your physical rigidity vanished, your mind no longer thought of science or variables, it was completely blank, at Sana's mercy. Now you moved only guided by your animal instincts, with the sole objective of returning that kiss with the same intensity.

Your eyes slowly closed again, intoxicated by Sana's scent. From her seat, Mina quickly noted every reaction, every slightest movement of your bodies; every physiological response you offered before her eyes was an extra point in your research project.

Sana slowly pulled away, breaking contact with a soft sigh and brushing her nose against yours in a gesture so tender it left you floating on air. When she opened her eyes, her pupils were dilated and a bright, almost triumphant smile lit up her face.

You remained motionless, your arms slowly falling to your sides, your lips tingling, and the heat emanating from your face could easily have kept you warm through the cold winter.

“My turn!” Momo announced, interrupting the magical moment.

“Give me a break, for God’s sake.” You said, trying to catch your breath, still reeling from the previous shock.

Momo smiled slightly at your plea and took your hand to guide you back to the stool where you had been sitting. With a swift movement, she straddled your lap completely, allowing you to wrap your arms around her waist, while she firmly gripped your shoulders with both hands.

The laboratory seemed to shrink suddenly. The proximity of your bodies, the heat you gave off, and the determination in her eyes made you swallow hard.

She ran one of her fingers along the cheek she had kissed a few minutes ago, tracing the path up to your neck.

“If we were somewhere else, I wouldn’t mind nibbling all over this neck.” She whispered in your ear in a way that made everything inside you crumble.

When your eyes met, she finally closed the distance between you, pressing her lips firmly against yours.

Unlike Sana's playful energy, Momo's kiss was direct, firm, and deep. She took her time, moving her lips with a deliberate slowness that sent shivers down your spine.

Your hands began to move with a mind of their own, one ending up on her back and the other at the back of her head, buried under her dark hair, tilting her further towards you.

A possessive move that surprised even you, but which she seemed to accept with pleasure, biting your lower lip, forcing you to open your mouth with a muffled moan to give Momo free rein to start playing with your tongue.

A deep, wet kiss, her tongue tangling with yours as it finished off what little brainpower you had left. You tasted an addictive flavor that made you completely lose track of time and space. The lab, the research, even your university career... everything ceased to exist in that moment.

Until Momo finally pulled away, she did so slowly, leaving one last, insistent tug on your lower lip that elicited a trembling sigh. She placed one of her hands directly on your chest, right over your heart, catching the frantic beating beneath her palm.

Sana continued to note down every sensory detail you had provided: mouth slightly open, eyes half-closed, and chest rising and falling violently in search of air.

“Impressive…” Momo murmured, adjusting her glasses slightly on her nose. “The supplemental oral impact has raised the heart rate by twenty percent more.”

Mina, who was watching the scene with her pen suspended in mid-air and nodded mechanically, noting down the data with a visibly trembling hand. She was so flushed she looked like she might faint at any moment.

Momo slid off your knees with a mischievous little smile, leaving you with a bit of breathing room and legs that felt like jelly.

“Okay, there’s only one more sample to close the field study and calculate the average.” Sana crossed her arms, tilting her head as she looked at Mina with eyes brimming with pure, amused malice.

“Mina-chan, it’s your turn to validate the final hypothesis.”

The girl in question swallowed hard, staring at her notebook as if searching for a way out. You knew you could stop it, but your body was on the verge of a hormonal meltdown, and that part of you, the one already completely adrift in limbo, desperately longed to see what would happen if the calm and cerebral Mina broke her own rules.

“I…” Mina slowly rose from her chair. You could catch a special glimmer in her eyes.

“As the group’s lead scientist… it is my duty to ensure the academic rigor of the project. We cannot leave an incomplete sample.”

She walked toward you with short steps, clutching a folder to her chest like a shield. When she stopped right in front of your seat, you noticed how she avoided your eyes for a few seconds, her gaze fixed on your lips, bitten by Momo.

Finally, she took a breath and looked up. Her dark eyes shone with a vulnerability that completely disarmed you. She dropped the folder to the floor with a soft thud and took another step, invading the last inch of your personal space. Her hands, cold but incredibly soft, slowly rose to cup your cheeks. The contrast of her cool touch against your burning skin made you sigh.

“For this final test, try to keep your eyes open,” Mina whispered with her face just inches from yours. “We need to see… your eye response directly.”

“Fine…” You answered, mesmerized, lost in her beautiful face.

And then, Mina kissed you.

If Sana and Momo's kisses had been a whirlwind of hormones and boldness, Mina's was an absolute yet devastating calm. Her lips rested on yours with extreme delicacy, but with a firmness you hadn't expected from her.

It was a slow, sweet, infinitely tender kiss making you feel a warmth that filled your chest. Her lips moved gently, fitting perfectly with yours, inviting you to follow a slow rhythm.

Your hands instinctively sought her wrists, gently holding her, wanting to freeze time in that empty laboratory as your mind sank into a deep ocean.

When Mina finally pulled away, she did so slowly, examining each piece of information she had gathered. Her eyes shone shyly, but also with a spark of pride at the spell she had cast upon you. She stumbled back to her seat and immediately hid behind her notebook, completely speechless, her face buried in her hands.

The silence that settled in the lab was thick, almost electric. No one spoke for what felt like an eternity. You were emotionally exhausted, leaning against the back of the table, trying to remember how the human respiratory system restarted.

It was in that moment of absolute silence, as you tried to put everything back in its place, that Momo suddenly broke the spell. She stood to one side, analyzing your posture with her arms crossed. Her gaze traveled slowly up your neck, down your still heaving chest, and finally settled much lower.

Your eyes instinctively followed the path of hers, and suddenly, the cold of harsh reality hit you like a bucket of ice water. The treacherous, obvious, biological, and inevitable physical reaction of your body stood out undeniably beneath the fabric of your pants after so much closeness, touching, kissing, and consecutive stimulation.

A mischievous, slow, and completely naughty smile began to appear on Momo's lips.

“Wow, it seems that the pleasurable physical stimulus has triggered a high-caliber secondary response. Look, Sana,” she remarked, pointing her finger downwards.

“Ah!” Sana stifled a scream of pure amusement as she realized, her eyes wide open, and ran towards the table at full speed.

"Information for the project! We need to measure the volume of the secondary stimulus for the conclusion! Pass me the pen, Mina!"

“What?! No! Put down that pen!” You screamed, snapping out of your trance. You frantically tried to cover yourself recovering the folder from the floor, sinking into the chair as your face burned so hot you felt like you were going to evaporate.

“It’s a physical reaction totally relevant to the hypothesis, we have to document it!” Sana joked amid laughter as Momo approached to help you hold the folder with a playful look.

“It’s not relevant, Sana! Momo, stop right there! Mina, tell them to stop please!” You pleaded desperately, on the verge of tears of shame.

Mina, hearing your cries for help, looked up from her notebook, glanced sideways at the hilarious scene of Sana mocking you and you curling up like a ball, and again hid her face in her arms on the table, trembling completely as an uncontrollable and contagious laugh took hold of her.

Finally, after ten minutes of pure pleading, chasing each other around the tables, and Sana and Momo's laughter echoing throughout the room, the chaos subsided. With all the collected data, they managed to finish writing the report—fortunately omitting the test subject's side effects—and organize their notes in a folder.

“Well, our duty to science is done for today!” Sana announced, stretching her arms lazily and grabbing her backpack.

“I’m hungry,” Momo added, getting off the stool and slinging her bag over her shoulder.

“If I don’t eat something now, my brain is really going to collapse.” Momo walked towards the exit, but just before crossing the threshold, she turned towards you and stuck her tongue out in a childish and mocking way, winking at you.

“I’ll go with you!” Sana, for her part, let out a giggle and blew a couple of kisses in the air with both hands before disappearing down the corridor, leaving behind the echo of her footsteps.

The lab fell into a sudden silence when you were left alone with Mina. The atmosphere, which a moment ago had been pure noise and jokes, became strangely intimate.

Mina began to slowly stuff the neatly arranged papers into a folder, as if trying to buy time. Her cheeks still held an adorable pink hue.

“Who… who do you think should be in charge of handing in the work tomorrow?” she whispered, breaking the ice without looking up from her hands.

“I can take it if you want. After all, you did most of the writing. And well… you’ve had to put up with all this.” You replied, moving closer to her side of the table.

Mina let out a soft giggle, closing the folder.

"Okay. I trust you."

She grabbed her things and started walking toward the exit. It seemed like it was all going to end there, politely and discreetly, as your interactions had always been. But your heart, which had already experienced being close to her, couldn't hold back this time.

Just as Mina walked past you, you gently took her arm. She stopped, surprised, but before she could say a word, you pulled her firmly, drawing her directly toward you.

Your other hand traveled to her waist, trapping it, and you closed the distance, pressing your lips to hers in a clean, confident, and deep kiss. You weren't going to be a submissive test subject anymore.

Mina's eyes widened in shock, and she let go of her things in surprise. The folder fell to the floor with a thud, scattering a couple of papers, but neither of you cared.

Within seconds, you felt Mina's body relax completely against yours; she let out a soft sigh and wrapped her arms around your neck, returning the kiss with an intensity that immediately quickened your pulse. Her lips were as warm and sweet as you remembered.

When you finally separated for lack of air, you kept your hands on her waist. Mina looked at you with trembling eyelashes and ragged breathing, completely disarmed.

A lopsided smile, confident and somewhat mischievous, appeared on your lips.

“I’ve been waiting for a moment like this for far too long, Mina,” you said, looking her straight in the eyes. “Did you really think I wasn’t going to do anything about it after what happened earlier?”

She could only bury her face in your chest, letting out a shy whimper but hugging you a little tighter. The hypothesis was definitely proven.

A week later, the tension in the lab transformed into pure academic glory when the professor announced the highest grade in front of the entire class: Yours.

Mina and you, sitting on your usual seats, glanced at each other and shared a satisfied smile. Every damn second of racing heart had been worth it.

However, the formality of the classroom was immediately broken when, a few rows back, Momo and Sana burst into shouts of joy giving each other high-fives and making such a racket that the teacher had to glare at them to make them be quiet, although they continued celebrating in whispers.

When class ended, you walked out into the hallway with your backpack slung over your shoulder, feeling like the king of the campus. But your peace didn't last long. Before you could reach the stairs, three familiar figures rushed up to you.

Sana and Momo appeared on either side of your body, flanking you with identical, mischievous smiles, while Mina walked a step behind, observing the scene with quiet amusement.

“Good job, groupmate,” Momo commented, giving you a playful pat on the back.

“We’re a great team, aren’t we?” Sana continued, tilting her head.

Before you could respond, they both coordinated their steps and, with perfect timing, gently pushed you back until you hit the corridor wall, trapping you. Mina positioned herself directly in front, completing the circle. The corridor was half empty, but the space felt as small and warm as the lab.

Momo held your chin and Sana wrapped her arms around your neck. Before you could react, they leaned in and kissed you again. Momo captured the corner of your lips with a firm touch, Sana planted one of her loud kisses on your cheek, while Mina stepped forward and gave you a quick, tender kiss right on your forehead, leaving your cheeks burning once more.

“H-hey…” you managed to say, trying to regain your composure as passersby glanced at you. “Homework is done. There’s nothing more to investigate.”

“Consider it a reward for your services to science,” Sana replied, winking at you cheekily.

You rubbed the back of your neck, glancing at the three most amazing girls in the school, who were watching you with absolute adoration and a desire to keep playing. The fear and embarrassment of last week had vanished, replaced by a newfound confidence that made your heart race for very different reasons.

"And... how can I get more of those rewards?" you asked, holding their gaze despite the blush spreading across your face.

Sana, Momo, and Mina exchanged a look. All three smiled at the same time—a look full of promise that left no room for doubt.

The months to come were going to be, scientifically speaking, unforgettable.