My grandfather actually said this once. I later heard it again somewhere else, but I don't remember where. Apparently, in Oklahoma, this is actually an expression people use.

Usage was something like "Don't just stand around there with your teeth in your mouth" -- in some garbled way it was supposed to imply that by standing around with my teeth in my mouth, I was being useless. I don't remember the exact wording, but it was still the coolest thing I had ever heard.