Bored and horny, this stepbrother retreats to his room, pulling out his throbbing cock. He strokes it vigorously, his pre-cum dripping onto his eager hand. Suddenly, his sister bursts in, catching him mid-act. Instead of being embarrassed, she's intrigued. She watches hungrily as he continues to jerk off, her own hand sneaking between her legs to rub her damp panties.