Underpants parties are events that take place when two adults (or more) are quite fond of of one another and they decide to have a party where the only articles of clothing allowed to be worn are underpants and accessories. They are invitation *only*.
Brandon: I hear that Ava is throwing an Underpants party.
Kathan: Oh I know, I was given an invitation.
Kathan: Oh I know, I was given an invitation.
by epicavacado August 13, 2015