When the humanfacial nerve realises that something has indeed landed on their face. Causing the motion of the face to move from side to side viciously.
"Gee look at that guy he must be having a full on JitterFest"
"Now if you'd like to be a Jitter Bug, first thing you do get yourself a jug; put whiskey, wine, and gin within, shake it all up and then begin. Get yourself a cup and start to toss, come on Jack you're drinking Jitter Sauce."
-Cab Calloway
It's something that is included on a modded controller. It takes advantage of the XYY glitch in the call of duty sieries. It makes shot guns and sniper rifles automatic
A. What kind of mod do you got? You shootfuckingfast B. Jitter mod