b. im balls deep in my homework right now
a. that party last week was nuts
b. yeah! it was balls deep!
a. hear about that volcano eruption?
b. yeah it totally wreecked my neighborhood
c. eh, I was balls deep in the lava
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?!"