A brother's curiosity leads him to the bathroom, where he finds his sister lost in her own world, fingers buried deep in her ass. Her eyes meet his in the mirror, challenging him, daring him to join. He steps closer, his cock tenting his pants. She grins, backing her ass up to him, inviting him to take over. He obliges, his fingers joining hers, stretching her tight hole as she moans, pushing back against him, hungry for more.