Locked in his room, the stepson's mind races with forbidden thoughts. He's been caught staring at his stepmom's ass, her legs, her cleavage, and now he can't stop. He's alone, his cock straining against his boxers. He pulls them down, letting his hard-on spring free. He strokes, his eyes closed, imagining his stepmom's touch. He thinks about her catching him, about her reaction. His strokes become faster, more urgent. He's close. He opens his eyes, looks at his stepmom's panties draped over his desk chair, and comes, his body shuddering as he spills his load onto the floor, his heart pounding with the thrill of his taboo fantasy.