HUNTC-514 Hikaru Minazuki, Kana Yura, Nana Ayami

The older brother is disgusted and avoided by his younger sister. His sisters, having fun with their friends, use him as a punishment in a game. The first punishment is a mild one: they lift their skirts and show their panties in front of him. But as their excitement builds, the sisters make the punishments increasingly hardcore: oral sex... fingering... intercourse... The brother simply accepts these acts without understanding their meaning.