Awakened by his sister's soft moans, a curious brother investigates, finding her in the bathroom, pants down, hand feverishly working her pussy. She gasps, caught mid-act, but he's intrigued, his own cock tenting his pajamas. They exchange shy smiles, and he joins her, stroking his length against the cool tile. Her eyes widen at its size, and she licks her lips, inching closer. Just as they're about to make their first touch, the front door creaks open, freezing them in their intimate moment.