a bitchdown is similar to a smackdown or a showdown except its with two white girls (mostly cheerleaders) and its when the two girls bitch eachother out
its also an epic showdown between two or more angry females involving yelling, catfights, and bitchslapping
sally and anne had a bitchdown after sally lied and stole annes boyfriend
Generally when someone has been "bitching you out" and you counter them.
I brought the bitchdown to that chick!