Said after when something crazy/unusual/weird happens, or is said. Usually pronounced "Buz". Kind of like What the Fuck, Holy shit and Huh? Rolled into one.
Dude 1: My girlfriend choked on my condom when it came off in her mouth. Dude 2: Buz!!!
A very best friend. Short for "bosom buddies".
You can only have one.
Me: Hi Buz!
Nate: Hey Buz!