It's an onomatopeia for a drum technique normally accompanying the conclusion of a cheesy joke or
a comedy pratfall (where someone is made to look like an idiot by their own devising - such as falling on a banana skin they earlier discarded). It consists of two fast rimshots and a splash
cymbal - producing the sound "badum tish".
#1: What does
bees do if they don't want to drive?
#2: Dunno
#1: Wait at
the buzz stop! Haha!
#2:
Badum tish!
