We were both home for the weekend, adults who should have known better, but the house was empty and the old tension snapped like a rubber band. I walked into the kitchen and there she was, my sister, bent over the counter in a tiny tank top and shorts that barely covered her ass. "You keep staring like that and I'm gonna think you want something," she said, not even turning around.
"I want to fuck you," I told her straight out. No buildup, no games. "Been wanting to bend you over and shove my cock in that tight cunt since we were old enough to know better."
She froze for a second, then pushed back against the counter so her ass lifted. "Then do it. Door's locked. Mom and Dad won't be back till tomorrow."
I didn't waste time. I stepped up, yanked her shorts down to her knees, and slapped her bare ass hard enough to leave a red handprint.
Her pussy was already wet, lips puffy and glistening. I spit on my fingers and rubbed her clit once, twice, then lined my cock up and drove in balls-deep in one thrust.
"Fuck yes," she groaned, pushing back to take every inch. "Harder. Use me like the dirty sister I am."
I gripped her hips and started pounding, the sound of skin slapping skin filling the kitchen. Her cunt gripped me tight, hot and slick, juices running down my balls with every slam. I reached around and pinched her nipples through the tank top until she yelped. "You like your brother's cock stretching this pussy?" I growled.
"God, yes. Don't stop. Fill me up."
I pulled out, spun her around, and lifted her onto the counter. Her legs spread wide and I shoved back inside, fucking her so deep her tits bounced with every thrust. She reached down and rubbed her clit fast, eyes locked on mine. "Tell me it's wrong," she panted. "Tell me how fucked up this is."
"It's incest, you little slut. I'm balls-deep in my own sister's cunt and I'm gonna cum inside you."
That pushed her over. She came hard, cunt pulsing around my cock, soaking the counter. I didn't let up. I kept slamming until my own orgasm hit, pumping thick ropes of cum deep into her. When I pulled out, it leaked out of her swollen pussy and dripped onto the floor.
We weren't done. She slid off the counter, dropped to her knees, and sucked me clean, tasting our mixed cum on my shaft. Then she bent over the kitchen table and spread her cheeks. "Now do my ass. Make it hurt."
I worked spit into her tight hole and pushed my cock in slow at first, then harder once she relaxed. She moaned loud, pushing back, taking it all. I fucked her ass raw while she fingered her cum-filled pussy, both of us grunting like animals. When I came again, I stayed buried, flooding her ass too.
We spent the rest of the night moving from room to room, fucking in every position, on every surface. By morning her pussy and ass were sore, my cock raw, and we both knew this taboo shit was only getting started. We cleaned up just enough to look normal when our parents got home, but the secret was already thick between us. Next time the house was empty, we'd do it all again, dirtier.
