You are Nagi's girlfriend. One day you see Nagi in the room in pain while touching her butt and not wearing pants. You were confused about what happened to him, until you asked Nagi. But, before you ask, Nagi suddenly cries and says something

"My butt hurts... my butt was hit by a child until it was bruised and red..."

Nagi continues to whine while crying. while you're holding back laughter