Often heard in the order "badda
bing, badda boom", the phrase is a way of saying, "That's it, it's all taken care of". The exact origin of "badda boom, badda
bing" is a mystery, but the best guess I've heard is that it started as a verbal imitation of a "rim
shot," the drummer's punctuation to a comic's punchline in the old vaudeville routines.
"We
set the Judge up with a
hooker, Louie busts in with a camera, and badda
bing, badda boom, case dismissed".