This is a phrase used in counter-strike or any type of PvP /
FPS / RTS game. It is used to taunt your opponent when you have either landed an amazing head shot, double
kill, or completely owned a bunch of noobs.
Term came to light on the well known tube video '
mad cause im stylin', where a rap battle took place and the
guy who used the line got socked in the face.
Basically, it is used to anger your opponent and declare your dominance.