Do you find that you have trouble staying away from nicotine when alcohol gets involved? This episode should help. The reason why it is so much more difficult to not vape when you drink is because alcohol inhibits your power to regulate your emotions and cravings. It makes total sense that drinking is a vulerable place for quitters to relapse.
If you ever mess up and vape when you said you weren't going to, the best thing you can do is to look at the situation and what occured from a place of genuine curiousity, not judgement.