A popular technique employed in many first person shooter games whereby the
player attempting to perform the skill (the jag), moves around in an erratic, zigzag like fashion, making it difficult for enemies to hit the
player.
The term jagging was coined and popularized by the
player CurtMACHINEHEAD in the game Gears of War, in which he dominated by use of a glitch known as the "lobster trot" in combination with his jagging technique.
Sniper (frustrated): FOR FUCK
SAKE I CAN'T
HIT HIM HE'S JAGGING!
CurtMACHINEHEAD: You can't hit me, for I have mastered the black
art of jagging.