Tension builds between the siblings as they find themselves alone in the house. The brother, unable to keep his eyes off his sister's curves, retreats to the bathroom, his cock throbbing. She follows, her curiosity piqued. He's mid-stroke when she enters, catching him off guard. Instead of leaving, she leans against the door, watching him, her own arousal evident. They're both past the point of no return, their mutual masturbation escalating, bodies tensing, breaths coming in ragged gasps, until they're left panting, their taboo secret hanging heavy in the steam-filled room.