When chaos arrives; when something pops off; If you can't take anymore
Lady1: I caught him cheating.
Lady 2: I'm sorry to hear.
Lady 1: I see the side chick now.
Lady 2: Oh Shits about to hit the fan.

Shit has hit the fan; Life just got real!
by Cutie kay December 21, 2016
A way of announcing to people that something really dramatic has happened. Usually involves chaos and often violence.
"Hey have you seen what's going on out there?"
"No what is it?"
"Jack got caught cheating on his girlfriend and the shit has hit the fan"
by Gump92 October 25, 2013