Mike was twenty-three and his sister Lisa was nineteen when it finally happened. They had the house to themselves for the weekend, parents gone to the lake. Lisa walked into the living room wearing nothing but a towel that slipped off her hips the second she bent over to grab the remote. Her round ass cheeks spread just enough to show the tight pink ring of her asshole. Mike stared, cock already thickening in his shorts.
"Fuck, Lisa, put some clothes on," he said, but his voice came out thick.
She looked back over her shoulder and grinned. "Why? You've seen me naked before. Remember when we used to skinny-dip in the pool at night?" She straightened up, letting the towel fall completely. Her tits were small and perky, nipples hard. Her shaved pussy lips glistened. "Or are you just scared you'll get hard looking at your little sister's asshole?"
Mike stood up. His shorts hit the floor. His cock sprang out, thick and veined, already leaking. "You want to play that game? Fine. Get on your knees."
Lisa dropped without hesitation. She wrapped her hand around his shaft and licked the head, tasting the precum. "Mmm, big brother's cock tastes good." She opened her mouth and took him deep, gagging when he hit the back of her throat. Spit ran down her chin onto her tits. Mike grabbed her hair and fucked her face, watching his cock disappear between her lips.
After a few minutes he pulled out. "Turn around. Hands on the couch."
She obeyed, arching her back so her ass pushed out. Mike spread her cheeks with both hands, staring at the tight little asshole he'd been thinking about for months. He spat on it, rubbed the spit around with his thumb, then pressed the head of his cock against the ring. "You want your big brother to fuck this asshole raw?"
"Yes," she moaned. "Shove it in. Stretch your little sister's asshole."
He pushed. The head popped past the tight muscle. Lisa gasped, fingers digging into the couch cushions. Mike kept pushing, inch by inch, until his balls rested against her pussy. Her asshole clenched around his shaft like a fist. He started thrusting, slow at first, then harder. The wet sound of his cock sliding in and out of her ass filled the room.
"Fuck, it's so tight," he growled. He reached under her and rubbed her clit while he pounded her asshole. Lisa pushed back, meeting every thrust. "Harder, Mike. Wreck it. Make it gape."
He pulled out, spat on her hole again, and slammed back in. Her asshole stretched around him, red and shiny with spit and precum. He fucked her like that for a long time, changing angles, making her whimper and beg. When he felt his balls tighten he yanked out and flipped her onto her back on the floor. He lifted her legs over his shoulders and drove back into her asshole, watching her face while he fucked her.
Lisa reached down and fingered her own pussy, three fingers sliding in easily while her brother's cock stretched her ass. "I'm gonna come," she panted. "Don't stop. Come in my asshole, big brother.
Fill it up."
Mike's thrusts turned short and brutal. He buried himself to the hilt and came hard, pumping thick ropes of cum deep into her guts. Lisa's orgasm hit at the same time, her asshole pulsing around his cock, her pussy squirting onto his stomach. He stayed inside her until he softened, then slowly pulled out. Her asshole stayed open for a moment, a creamy white trickle of his load leaking out and running down toward her pussy.
They didn't stop there. Later that night he took her again in the shower, bending her over the tub and fucking her asshole while hot water ran over them. The next morning she woke him up by sitting on his face, grinding her pussy on his tongue while she sucked his cock, then climbed on and took him in her ass again, riding him reverse cowgirl so he could watch every inch disappear.
By Sunday night her asshole was puffy and sore, but she still begged him for one more load before their parents came home. Mike gave it to her, slow and deep, while she lay on her stomach with her legs spread, moaning into the pillow every time he bottomed out.
They cleaned up, put clothes on, and pretended nothing had changed. But every time their eyes met after that weekend, they both knew it would happen again.
