Day 5

The morning light felt heavier somehow. Both of you knew this was the last full day before your parents returned tomorrow evening. Mayu was already awake when you opened your eyes. She was sitting on the edge of the bed wearing nothing but the black collar, her thighs pressed together tightly.

“I’ve been wet since I woke up,” she confessed softly, cheeks pink. “Thinking about today… about you edging me until I break.”

She crawled over and kissed you deeply, almost desperately.

“Please be cruel today. Don’t let me cum easily.”

You prepared everything while Mayu waited obediently on her bed. You cuffed her wrists and ankles to the four corners of the bed, spreading her petite body wide open in a perfect X-shape. Her small breasts rose and fell quickly with nervous excitement, pink nipples already stiff. Her shaved, puffy pussy was visibly glistening, inner thighs shiny with her arousal.

You leaned over her and fastened the thick blindfold over her eyes, plunging her into darkness.

“Can you see anything?” you asked.

“No… I’m completely helpless,” she whispered, voice trembling with anticipation. She tested the cuffs, pulling lightly. They held firm.

You started slow.

You ran your fingers gently over her inner thighs, teasing the sensitive skin right next to her dripping slit but never touching it. Mayu whimpered and tried to lift her hips, but the restraints kept her pinned down. You spent nearly twenty minutes just teasing her,  light touches, blowing cool air on her clit, tracing her folds with one fingertip.

By the time you finally turned on the fucking machine, she was already begging.

You positioned the thick dildo at her entrance and pushed it inside her soaked pussy in one smooth motion. Mayu moaned loudly, back arching. You set the machine to a slow, deep rhythm, enough to keep her stimulated, but nowhere near enough to make her cum.

For the next two hours, you edged her mercilessly.

You increased the speed gradually, letting the machine fuck her faster and deeper, only to slow it down or stop completely right when her moans grew desperate and her thighs started shaking. Every time she got close, you turned the machine off and used your mouth or fingers to keep her right on the edge without letting her tip over.

Mayu lost her shyness completely after the third edge.

“Please… please let me cum… I’ll do anything—” she sobbed, voice hoarse. “I can’t take it anymore… my pussy feels so empty when you stop…”

You brought the machine back to a brutal pace, the wet schlick-schlick-schlick of the dildo pounding her drenched cunt filling the room. Mayu’s hips bucked wildly against the restraints, drool slipping from the corner of her mouth as she cried out.

“I’m so close– I’m right there– please don’t stop this tim—e!”

You stopped the machine again.

Mayu screamed in frustration, tears soaking the blindfold. Her whole body trembled violently. Her pussy was swollen, bright red, and gaping slightly every time the dildo withdrew, clenching desperately around nothing.

You did this again and again, bringing her to the very brink, sometimes with the machine, sometimes while fucking her yourself, sometimes with her biggest dildo while the machine teased her clit with a vibrating attachment.

By the fourth hour, Mayu was a broken, babbling mess.

“I’m your toy… I’m your slutty little step-sister… please ruin me… I need to cum so badly it hurts…” she cried, voice cracking. Her pussy was continuously leaking, a large wet spot soaked into the sheets beneath her ass.

You finally decided she had earned it.

You set the fucking machine to its highest speed and deepest stroke. The motor whirred loudly as it hammered her ruined pussy without mercy. At the same time, you climbed between her spread legs, pressed the powerful wand vibrator directly against her swollen clit, and turned it on maximum.

Mayu’s entire body went rigid.

“Oh my god— oh fuck– I’m– I’m—!!”

The orgasm hit her like a freight train.

Mayu screamed at the top of her lungs as she finally came. Her pussy clamped down hard around the pistoning dildo, then suddenly exploded. A powerful, clear jet of squirt shot out around the thick silicone cock, spraying violently across the bed. You kept the machine and wand going without mercy.

She kept squirting.

Wave after wave of girl-cum gushed out of her in long, powerful fountains, soaking her thighs, the machine, the sheets, and even reaching your chest. Her body convulsed violently in the cuffs, back arched so high only her head and heels touched the bed. Her screams turned into broken, animalistic wails as the overstimulation forced her into a continuous, shattering orgasm.

You didn’t stop.

The machine kept pounding her spasming cunt and the wand vibrated relentlessly on her over-sensitive clit. Mayu kept squirting in smaller, weaker bursts, her body jerking and twitching uncontrollably as tears poured from under the blindfold.

“Too much–! Too much–! I can’t stop cumming–!!” she wailed, voice completely raw.

Only after her fifth consecutive squirt did you finally turn everything off.

Mayu collapsed into the mattress, limp and shaking. Her chest heaved wildly as she gasped for air. Her pussy continued to twitch and pulse visibly, tiny aftershocks of squirt still leaking out in weak dribbles.

You removed the blindfold. Mayu’s eyes were glassy and unfocused, cheeks streaked with tears. She looked completely fucked stupid.

You uncuffed her gently and pulled her small, exhausted body into your arms. She trembled against you, burying her face in your neck.

“I’ve never… cum that hard in my life…” she whispered weakly. “I thought I was going to pass out…”

After a long silence, she let out a tiny, tired giggle.

“Our parents come back tomorrow… but I don’t think I can walk properly right now. My legs are completely useless.”

She looked up at you with that familiar shy-yet-filthy smile, even through her exhaustion.

“…We still have tonight. One more round before they return?”

The week was almost over, but Mayu clearly wasn’t ready to go back to being “just step-siblings” yet.