When your poop is so long that the bottom tip sticks at the bottom of the toilet and the top end falls forward and slaps your testicles. Imitating being slapped like a whale's tail.
Trevor called me during dinner to tell me about his comical whale's tail. It was a Whale of a tale.
Term used to describe the visible part of a thong on a chick's butt when worn with low rise pants - resembles a whale's tail. (I say chick because I don't want to see a guy wearing this.)
That whale's tail really accentuates her ass!