What the hell is the wazoo where is it and why do people have money coming out of it?
You’re kidding, right?
Its your ass and if you have lots of extra money it comes out everywhere.
On the off chance that you actually wanted a factual answer, the only such answer is that it’s a coined word used only in that figure of speech, and doesn’t really mean anything. If you were just looking for humorous answers, then you should ask the question in MPSIMS. Either way, I’m closing this thread.