it mean working really hard
This means they want their burger on a bun.
I worked hard or I used much effort
Buttocks
Busting your balls is an idiom that means working very hard at something.
Busting was created in 1974.
I have no idea what you mean by this question.
Support
"bun"
Its a term of endearment.
kidney function
Busting Vegas was created in 2005.