I think your Beast is chewing a hole in the fence. At first you are able to ignore it, but if the hole gets bigger and bigger, that's where the "wham" comes in.
When the sudden urge to drink becomes irresistible, recognize that your Beast has pushed its big fat body all the way through the fence. Almost.
My suggestion would be to prepare a plan for when this happens. When the Beast is bearing down on you, hot breath on your neck, have a concrete plan of action. Mine is to recover my "mantra" that I am a non-drinker. Period. End of story. I do what non-drinkers do. Period.
Bad day? Have a plan for what you do to feel better that does not involve drinking. Recognize your weak places, your most sensitive triggers. I can't tell you what to do to keep the "fence" strong and in repair. Imagery helps me, but not everyone.
Ideas?
FT