How many times have you said that you would have just one or two and end up doing a lot more? Isn't it insane to think that this time would be any different, that you really can pick up just one? Moreover, do you really only want just one or do you want to have enough to get inebriated? Instead of picking up a drug, be still and connect to a Higher Power. This can be simply breathing without anger, judgment or intellectualization. When we just breathe while letting our compulsive thoughts go in and then out of our minds, we are using a Higher Power to stay sober.
Don't lie to yourself. Even in the unlikely event you can exercise self control to the extent where you could have just one for awhile, how long will it be before you are off and running again? Don't pick up the first drink or drug. Breathe deep. Slowly go back over this message and focus on each word to redirect your thinking.