It was the middle of July when my sister Emily and I ended up alone in the family cabin. Our parents had bailed last minute for some work thing, leaving us two eighteen-year-olds with the place to ourselves for two weeks. The air was thick and sticky, the kind that made clothes feel pointless. Emily walked around in nothing but a tiny tank top and shorts that barely covered her ass, her tits pushing against the thin fabric every time she bent over.
I tried to ignore it at first. But on the third night, after a few beers on the porch, she caught me staring. "You keep looking at my tits like you want to fuck them," she said straight out, no teasing. Her voice was low and dirty. "Go ahead and say it."
"Fuck yes, I want to fuck them," I told her. "And your pussy. And that tight ass."
She stood up, peeled off the tank top, and let her heavy tits bounce free. Nipples already hard. "Then stop talking and do it."
I grabbed her right there on the porch, spun her around, and yanked her shorts down. Her pussy was shaved smooth and already dripping. I shoved two fingers inside without warning, pumping hard while she moaned and pushed back against my hand. "Goddamn, you're soaked," I growled. "Been wanting your brother's cock all week, haven't you?"
"Yes," she panted. "Fuck me like you mean it."
I dropped my shorts, lined up my thick cock, and slammed into her from behind in one thrust. Her cunt gripped me tight and hot, sucking me in deep. I fucked her raw and fast, the wooden railing creaking under us. Skin slapped loud in the night air. Every stroke made her juices run down my balls. She reached back and spread her ass cheeks wider so I could pound her harder.
"Harder, fuck your sister harder," she begged. I did, gripping her hips and driving in balls-deep until she came with a loud cry, her pussy clenching and squirting a little around my cock.
We didn't stop there. I pulled out, spun her, and shoved my cock between her tits. She squeezed them together and let me fuck her cleavage while she licked the head every time it popped out. Spit and precum made everything slick. When I was close, I pulled her up and bent her over the table instead, spreading her legs wide and driving back into that wet hole.
The next days blurred into nonstop fucking.
Morning blowjobs in the kitchen while coffee brewed, her on her knees gagging on my cock until I shot down her throat. Afternoon fucks in the lake, her legs wrapped around me while I held her up and pounded her standing in the water. Nighttime anal on the living room floor, me working my cock into her tight ass after lubing it with her own pussy cream, her screaming for more as I stretched her open.
One afternoon it got even filthier. She climbed on top in the bedroom, sank down on my cock reverse cowgirl, and rode me while she played with her clit. "Tell me how nasty this is," she demanded. "Tell me you're fucking your own sister."
"I'm balls-deep in my sister's cunt," I grunted, slapping her ass red. "Filling her up like a slut."
She came again, then spun around and kept riding until I exploded inside her, pumping thick loads deep in her pussy. We didn't use condoms once. She loved the feeling of my cum leaking out of her all day.
By the end of the vacation we were fucking in every room, every position, raw and loud and without a single ounce of shame. The heat made us sweat and slide against each other, bodies slick and desperate. When our parents finally texted they were coming back, we just kept going one last time, her bent over the couch taking every inch while we both came hard and messy.
We cleaned up, acted normal when they arrived, but we both knew this wasn't the end. That hot summer had changed everything.
