It can also be used to imply that the action or event was taken to its extreme, with no other possible courses of actions available.
Me: "Ahahahahahaha!" *accidently walks off cliff on map Jungle in Black Ops
Person 1: "Dude, we're balls deep in the Middle East now that Obama's president."
Person 2: "Not as deep as I was in your mom last night."
Person 1: "WTF?!"
2) (adj) generally, the act of doing any activity hardcore, all out, and as fully as possible.
A: Balls deep in some slut's filth.
ex 2. We hit the bars balls deep last night- I feel shitty.
2.can be used as an expression for something overwhelming, ridiculous, exaggerated, or to refer to a large number of things. Also as an affirmative when answering a question
"Are you in to go to tijuana tonight? IM BALLS DEEP"