Eunwoo: saw Binnie show his abs to his friends.

- That night -

Binnie: Where are all my clothes? Give it back to me.

Eunwoo: No, it's fair now.

Binnie: Huh?

Eunwoo: It's not fair that those guys saw you so I have to watch you nude, then.

Binnie: ...

After that, no one have ever seen Binnie's abs.