Innocent teen sister, unaware of her stepbrother's voyeuristic tendencies, indulges in daily self-pleasure, her moans echoing through the empty house. Today, however, he's home early and catches her mid-act, her hand wrapped around her clit, fingers glistening. She freezes, eyes wide, as he watches from the doorway, his own arousal evident. Embarrassed but excited, she continues, putting on a show, until he can't help but join in, stroking his cock openly, their taboo encounter intensifying her pleasure.