As the clock ticks towards midnight, the siblings huddle together in their shared bedroom, each lost in their own thoughts. The brother, his mind filled with forbidden images, can't help but let his hand drift down to his crotch, his cock already rock hard. His sister, hearing the soft sounds of his pleasure, turns to look at him, her eyes widening at the sight of his massive erection straining against his pajama pants. Their eyes meet, and in that moment, all bets are off. She reaches out, her hand tentatively wrapping around his cock, her fingers barely able to encircle the thick shaft. He groans, his hips bucking as she begins to stroke him, her hand moving in slow, deliberate motions.