A sister dozing off in front of her brother. Seeing her defenseless state, the brother, despite knowing she's his sister, can't help but get aroused and starts masturbating. His lewd pranks on his unsuspecting sister escalate. But when she finds out, she is disgusted. Still, the kind-hearted sister can't bring herself to hate her brother and says, 'It must be because you've been holding it in for too long,' and offers to help with the masturbation...!
