She walked into the living room wearing nothing but an old t-shirt that barely covered her ass. I knew right away this was trouble. My sister had always been the one who pushed things too far, and after our parents left for the weekend, she was already testing me.
"Hey, big brother," she said, voice low and teasing. She climbed onto the couch and straddled my lap without asking. Her bare pussy pressed right against the bulge in my jeans. "You look tense. Want me to fix that?"
I should have pushed her off. Instead my hands went to her hips. "This is fucked up," I muttered.
"Yeah, and you’re already hard," she answered, grinding down slow and heavy. Her hips started that familiar rocking motion, humping her slick cunt along the length of my cock through my pants. Every bounce made her tits jiggle under the thin shirt. She wasn’t wearing panties. I could feel how wet she was getting, soaking the denim.
She leaned in, breath hot on my ear. "Remember when we used to do this? You’d let me hump your lap until I came, then you’d jerk off in the bathroom like a good boy. Not tonight."
Her hips picked up speed. She bounced harder, ass slapping down against my thighs while she rubbed her clit right on the ridge of my cock. I could smell her arousal, sweet and dirty. My hands slid under the shirt and grabbed her tits, squeezing hard. She moaned and bounced faster, the couch creaking under us.
"Fuck, sis, you’re dripping all over me," I growled.
"Shut up and let me use your cock," she shot back, grinding in tight circles now, bouncing with short, desperate strokes. Her pussy lips spread around the thick outline in my jeans. She was getting herself off on me, just like she always had, only this time neither of us was stopping.
I couldn’t take it. I yanked my zipper down and pulled my cock out. It slapped up against her bare stomach, thick and leaking. She looked down, eyes dark, and immediately dropped her hips again. This time her wet slit rubbed directly along my bare shaft. The heat of her pussy was insane. She started humping in earnest, sliding up and down my length, clit catching on the head with every bounce.
"Put it in," she demanded.
"You sure?"
"Shut up and fuck your sister."
She lifted just enough, reached down, and notched the head of my cock at her entrance. Then she dropped. Her tight cunt swallowed me in one slick, hot slide. We both groaned loud. She was soaked, gripping me like a fist. She didn’t wait. She started bouncing hard, riding my lap with full strokes, ass slapping against my thighs, tits bouncing right in my face. I sucked one nipple into my mouth and she cried out, riding faster.
The wet sounds were filthy. Every time she dropped down, her pussy made a squelching noise around my cock. She kept talking dirty the whole time. "You like your little sister’s cunt? Feel how wet I am for you? Been wanting this dick for years."
I grabbed her ass and helped her bounce, lifting and slamming her down. Her juices ran down my balls and soaked the couch. She was relentless, grinding and bouncing, using my cock like a toy. When she came the first time, her whole body shook and her pussy clamped down so hard I almost lost it. She didn’t stop. She kept riding through the orgasm, chasing another one.
I flipped her onto her back on the couch and drove into her deep.
Her legs wrapped around me. "Harder," she begged. "Fuck me like you mean it." I pounded her, watching her tits bounce with every thrust. She reached down and rubbed her clit while I fucked her, eyes locked on mine. "Tell me it’s wrong," she panted.
"It’s wrong," I said, slamming in to the hilt. "You’re my sister and I’m buried in your cunt."
"Again."
"You’re my sister and I’m gonna fill you up."
She came again, screaming, nails digging into my back. I followed right after, pumping thick loads deep inside her while she kept bouncing her hips up to meet every spurt.
We didn’t stop there. She sucked me hard again on the floor, then climbed back on for another round of raw lap riding, this time facing away so I could watch her ass bounce. Later she bent over the kitchen table and I fucked her from behind until she squirted down her thighs. By morning we were both sore, covered in sweat and cum, and she was already climbing onto my lap again for one last slow, filthy grind before our parents came home.
She kissed me hard before she got off. "Next weekend they’re gone again," she whispered. "Don’t pretend you won’t let me hump this cock until I can’t walk straight."
I didn’t answer. I just watched her walk away, cum still leaking down her leg, already knowing I’d be waiting.
