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
The anxiety that ensues when one nears the end of a song in a rhythm game without yet missing any notes; the player is trying to "FC" (full combo) the song. Usually results in a really dumb mistake, in which case the player becomes furious and screams about how he or she will never waste money on his/her particular game again. Can pertain to any rhythm game (Guitar Hero, DDR, ITG, PIU, Beatmania, etc).