The origin of bust a cap meaning to discharge a firearm has become a general threat of violence with the implication that a gun will be involved. To threaten to bust a cap in someone's ass is also not intended to be anatomically specific, as kick ass or whip your ass are not descriptive of specific actions against someone's posterior. Ass as in "your ass" "my ass" etc refers more to the whole of the physical person. Further appellations such Honky, nigga, nigger, white boy, bitch, etc. are context dependent and may not have racial or gender implications.
"I'm gonna bust a cap in yo ass" "I would never bust a cap in your ass" "Please don't bust a cap in my ass" etc
by Doc@demon September 2, 2008

Byron: Your gay
Jonny: I will bust a cap in yo ass.
Byron: Try it.
Jonny:*Grabs Shotgun* Are you sure?
Byron: Yeah
Jonny: *Shoots Byron*
Jonny: I will bust a cap in yo ass.
Byron: Try it.
Jonny:*Grabs Shotgun* Are you sure?
Byron: Yeah
Jonny: *Shoots Byron*
by ?? January 31, 2003

To put a bullet in your body but not reserved soley for the ass region and usually intended to kill you!
Nigga! If you don't hand over that mote right now I am gonna bust a cap in yo ass!
You better start actin' like a grown ass man or I'm gonna bust a cap in you ass!!!
You better start actin' like a grown ass man or I'm gonna bust a cap in you ass!!!
by shizrok October 29, 2007

by Fidel May 9, 2004

"Bust a cap in yo Azkaban" is a threat that is simulteously a Harry Potter reference, and a Harry Potter in the Hood reference. "Azkaban", in this phrase, is a play on "ass" or "azz".
by herr0prease April 11, 2010

Something that dickheads say thinking they're saying "I'm gonna shoot you" but they're really saying "I'm going to ejaculate in your ass during anal sex" (usually homosexual)
by joveblue July 10, 2004

by DaQuisha August 20, 2003
