If playing a multiplayer game (with multiple controllers), press any button or use the C-Stick when it isn't your turn to taunt the opponent. When you taunt you can either use the C-stick for nice taunts or the D-pad for evil taunts. This makes it easy to do multiple taunts for maximum annoyance of other players for when you want the others to screw up in really competitive games where heavy bets have been placed. Just roll your thumbs on the d-pad and c-stick and it will make their mind twist and flip.