Onomatopoeia used to symbolize the sound that the drummer would make in a stereotypical stand-up comedy routine. Traditionally, after the comedian delivers the punch line.
You know this man is a kind loving man. He's got a real soft spot for young, up-and-coming comedians...it's called his @$$h0Le! Badoom tsss!
(and you have to pantomime playing the drums.)
Badoomps are those little yellow bumps sometimes in the middle of the road, appropriately named 'Badoomp' because that is the noise it makes when you drive over one in your car.
Note* don't drive over Badoomps in Fords, as it will most likely break your car.