A colloquial phrase referring to the basics of a job, task, or concept. Similar in
use to "the nuts and bolts" or "the ins and outs". Interestingly, all
three of these phrases contain double entendres, but are intended for
use in a generally non-sexual manner.
Oh, you're new here? Let me
show you the balls and the butts of running the cash register.
Jesse, shut up. You really
don't understand the balls and the butts of comedy.