In the quiet of his room, a boy tentatively wraps his hand around his growing erection, his heart pounding with anticipation and a touch of guilt. His sister, passing by, pauses, her eyes widening as she sees him. She shouldn't be watching, but she can't look away. He's inexperienced, his movements hesitant, but the sight of him touching himself sends a jolt of unexpected desire through her. She watches, hidden, as he picks up the pace, his breath coming in short gasps, until he finally comes, his body convulsing with pleasure.