my bad. If you are using automatic there is one already added. If stopped, hold B (or maybe its x) on the xbox controller. On the ps3 I know it's one of the 4 main face buttons, I believe it's square, but I'm not 100% positive because I don't have the game/controller mapping in front of me.
Edit - also, I should have lead with this, but thank you for taking the time to play, I'm glad you liked it, and I will be updating the controller references to reflect your feedback.