The siblings, their eyes locked, their bodies barely an inch apart, feel the heat building between them. The brother's cock twitches, tenting his pants, while his sister's nipples harden, pressing against her thin shirt. They're both aware of the taboo, the wrongness of their desire, but it only serves to fuel their ardor. She reaches out, her hand trembling, and touches his cock through his pants. He groans, his hips jerking forward. She unzips him, her eyes wide as his cock springs free, hard and ready. She strokes it, her hand slick with pre-cum, then guides it to her pussy, already wet and aching. He pushes into her, his hands gripping her hips, pulling her onto him. She moans, her head falling back, her hair brushing against his face. They move together, their bodies slapping, their breaths coming in ragged gasps, until they both come, their bodies convulsing, their cries muffled in the close space.