Mike and his sister Lisa had the private stretch of beach all to themselves that afternoon. Both over twenty-one, they had ditched the family house for the day, parking the car and walking down the path with towels and a cooler. Lisa stripped off her shorts and top right away, leaving just a tiny bikini that barely covered her tits and ass. Mike watched her bend over to spread the towel, his cock already twitching in his trunks.
"Fuck, you look good," he said, voice low and direct.
Lisa glanced back, smirking. "Yeah? Been staring at my ass all morning. You gonna do something about it or just jerk off in the sand?"
That was all it took. Mike dropped his trunks, his thick cock springing free, already half-hard. He grabbed her hips and yanked her back against him, grinding his dick between her ass cheeks through the thin bikini bottom. Lisa moaned and pushed back, rubbing against him.
"Get that suit off," he growled. She untied the strings fast, letting the top and bottom fall. Her tits bounced free, nipples stiff, and her shaved pussy was already wet and glistening. Mike spun her around, shoved her down onto the towel on all fours, and spread her legs wide. He spit on his hand, rubbed it over his cock, and slammed into her from behind in one hard thrust.
Lisa cried out, "Fuck yes, brother, fill that pussy." Mike gripped her hips and started pounding, his balls slapping her clit with every stroke. The wet sounds of his cock driving into her tight cunt mixed with the waves. He reached around and rubbed her clit hard and fast, making her push back harder, taking every inch.
He pulled out after a few minutes, flipped her onto her back, and spread her legs wide open. "Look at that dripping hole," he said, then buried his face between her thighs, licking and sucking her clit while two fingers pumped inside her. Lisa grabbed his hair and ground against his mouth, cursing and moaning. "Eat my pussy, you dirty fuck."
When she was shaking on the edge, Mike climbed on top, shoved his cock back in, and fucked her deep and steady, his chest pressed to her tits. They kissed messy and rough, tongues sliding, while he hammered her into the towel. Sand stuck to their skin but neither cared. He sat up, hooked her legs over his shoulders, and drilled down at a new angle that made her scream.
"Harder, brother, fuck me harder," Lisa begged. Mike obliged, slamming in balls-deep, sweat dripping off him. He pulled out again, flipped her onto her stomach, and mounted her prone, sliding back into her soaked pussy. One hand pinned her wrists above her head while the other reached under to pinch her nipples. He fucked her in long, grinding strokes, his mouth on her neck, biting and sucking marks into her skin.
Lisa came first, her cunt clenching and pulsing around his cock, juices soaking the towel. Mike kept going through her orgasm, then pulled out and flipped her again so she could suck him. She took his cock deep, tasting her own pussy on him, bobbing fast while he held her head and fucked her throat. When he was close he pulled back, stroked twice, and shot thick ropes of cum across her tits and stomach.
They lay there catching their breath, the sun beating down, waves still rolling in. Mike smeared his cum over her skin with his fingers, then slid them into her mouth so she could lick them clean. Lisa smiled around his fingers. "Round two in the water?"
He was already getting hard again. They ran naked into the surf, fucked standing up with her legs wrapped around him, water splashing around their joined bodies. Later they collapsed back on the towels, spent and sticky, already planning the next time they could sneak away. The afternoon stretched on, lazy and filthy, just the two of them and the empty beach.
