A chap ass is a word to describe someone being extremely annoying. In truth a chap is a type of legwear worn over jeans by cowboys, a chap ass is the same, but minus the jeans. So there ass in theory would be hanging out, therefor making it a chap ass.
Gosh Cal, shut your chap ass.
Did you see that dude, what a chap ass.
A sensation of rawness in the ass. Usually a direct side effect of severe diarrhea or a lengthy sentence in the federal penitentiary.
"Please hand me that can of Bag Balm, I have a terrible case of chap ass..."