She walked into the kitchen wearing nothing but one of my old t-shirts, the hem barely covering her ass. At twenty-two, my little sister still had that tight body that made my cock twitch every time I saw her. I was twenty-five, home for the weekend, and we had the house to ourselves while our parents were gone.
"Stop staring, perv," she said, but she bent over the counter to grab a bowl, giving me a full view of her bare pussy and the curve of her cheeks. No panties. She knew exactly what she was doing.
I didn't answer with words. I stepped up behind her, grabbed her hips, and ground my hard cock against her ass through my jeans. "You walk around like that and expect me to just look? Fuck that."
She pushed back against me, already wet. "Then do something about it, big brother."
I yanked the shirt up over her head and tossed it aside. Her tits bounced free, nipples hard. I spun her around, lifted her onto the counter, and spread her legs wide. Her pussy was shaved smooth and glistening. I dropped to my knees and buried my face between her thighs, licking her slit from bottom to top, sucking on her clit hard.
She grabbed my hair and moaned loud. "Fuck, yes. Eat that pussy."
I tongue-fucked her deep, then slid two fingers inside while I worked her clit. She came fast, thighs shaking around my head, juices running down my chin. "More," she gasped. "I need your cock."
I stood, dropped my jeans, and let my thick dick spring out. She wrapped her hand around it, stroking me rough. "God, you're so fucking big." Then she slid off the counter, got on her knees, and took me into her mouth. No teasing—she sucked hard, taking me to the back of her throat, gagging and drooling all over my balls.
I fucked her face, holding her head, thrusting deep until spit ran down her tits. When I couldn't take it anymore, I pulled her up, bent her over the counter again, and slammed into her pussy in one thrust. She was tight and hot, gripping me like a fist.
"Harder, brother. Fuck me like you mean it."
I pounded her, skin slapping loud, her ass rippling with every thrust. I reached around and rubbed her clit while I drove into her. She came again, screaming, pussy clenching and milking my cock. I didn't stop. I kept fucking her through it, then pulled out and pushed into her ass without warning.
She yelped, then pushed back. "Yes, fuck my ass. Stretch it."
I worked my cock into her tight hole, slow at first, then faster, balls-deep. I grabbed her hair and yanked her head back while I railed her. "You like your brother's cock in your ass, don't you?"
"Love it," she panted. "Fill me up."
I came hard, shooting thick ropes deep in her ass. When I pulled out, cum leaked down her thighs. She turned around, dropped to her knees again, and licked me clean, sucking every drop from my softening dick.

We didn't stop there. We moved to the couch, the shower, her bed. By the time our parents came home, we'd fucked in every room, raw and dirty, exactly how we both wanted it. She still sends me messages with that newsgroup name in the subject line when she needs more.