Buncakes -- though, thankfully, I have only heard one instructor go there...
Funny "word" story: Yesterday, I did Cuts & Curves, and Gilad was using tubing to work the "buttocks." (Or as he says: butt-TOCKS.) I was exercising sans tube. My youngest said, "Mommy, you don't have buttocks." Um...what? Turns out, she thought that buttocks must be referring to the tubing he was using, LOL. I quickly educated her on Gilad's favorite word for the glutes.