In the quiet of their shared bathroom, a brother and sister find themselves alone, their mutual masturbation session interrupted by a heated argument. As they stand naked and vulnerable, the sister's eyes flick down to her brother's thick, hard cock. She licks her lips, her pussy clenching with desire. She steps closer, her hand reaching out to grasp his shaft. He groans, his hips jerking forward. She strokes him, her thumb rubbing the pre-cum from his slit, before guiding him to her wet, waiting pussy. He slides in, filling her completely, and they begin to fuck, their bodies slapping together, their moans echoing off the tiles, their taboo incestuous passion consuming them.