IENF-241 A girl student's younger sister took pity on me, a useless guy, and agreed to let me do 'so-ko' (frottage) with her. But we both got too into it, and her pussy was soaking wet! So I slipped right in! "What!? It's inside?" But I couldn't stop and

A sister dozing off in front of her brother. Seeing her unguarded state, the brother, despite knowing she's his sister, can't help but get aroused and starts masturbating. The lewd pranks against the sister who doesn't wake up gradually escalate. But when the sister finds out, she is disgusted. Still, the kind-hearted sister can't bring herself to hate her brother and says, 'It must have been because you were too pent-up that a demon possessed you,' and offers to help with the masturbation...!