When things are calm, picture yourself being faced with a challenge and in your mind picture yourself, instead of acting out, doing something specific instead, like getting up and going to a different room, going for a jog, calling a friend, e-mailing someone, etc... Picture this scenario again and again, so that when the time comes, that will almost be your natural reaction to the situation.
Excellent advice! Basically what you're doing is re-training your subconscious to do something other than act out when you're challenged. Since this is an addiction, you're NOT in control when it happens. "Practicing" a different course of action helps re-train yourself to act differently when your subconscious is in charge and not you.