Hold back on the controller for as long as you want. When ready, change the direction directly forward, towards your opponent. At the same time you change direction, use any type of punch, and you will perform the "Sonic Boom."Continue Reading
Hold "back," away from your opponent, using your controller, as if you were blocking.
After holding back for any amount of time, change your direction towards your opponent.
At the same time you change the direction you are tilting, use any strength level of punch. If this is done simultaneously, Guile should perform the "Sonic Boom."