boompsie

n. slang term for butt, usually used by little children, but not limited to them.

Kid 1: Hey watch me!
Kid 2: Watch out!
Kid 1: Ow... I think I just fell on my boompsie...

Guy: Hey giiirrrll, I really like your boompsie.
Girl: What??
Guy: Nothin', nothin... barkeep!

by Slimjimnabil May 28, 2007