In the sultry heat of a summer afternoon, a curious teen girl sneaks into the bathroom, drawn by the sound of running water. Inside, she finds her equally intrigued younger brother, Cachan, already naked and hard, his hand working his stiff cock. She watches, mesmerized, as his hips thrust forward, his breath coming in ragged gasps. He doesn't notice her presence, lost in his own world of pleasure. She can't help but touch herself, her fingers slipping beneath her panties, matching his rhythm. The room fills with the sound of their mutual pleasure, their bodies straining towards release. Suddenly, Cachan's eyes fly open, catching her watching. They share a secret smile, their connection deepening as they continue, their bodies tensing and releasing in unison.