Bust my Buddy out

To take your dick out of your underwear

let me bust my buddy out to take a piss he's been in prison all day

Bust Out Buddy

To have sex with someone you've just met.

To have sex with someone- NSA.

To simply have sex with a person for no other reason than because you want to (no committment, rules or involvement.)

"Oh he was just my bust out buddy!"