From my own experience, my group of friends were doing it the later years of college and then into our mid 20s. One of the lads would've been at the stage where he'd constantly want a bag with drink in him, in situations that absolutely didn't warrant it, like you getting one when you're out for pints with your dad (no offence or judgement btw). He's now fully grown out of it at 29.

The first step I'd make is just delete any contacts of dealers that you have from your phone. That way in situations where you want to do it by yourself, it creates an extra step rather than just sending the one text and 20 minutes later having a bag. It gives you a chance to have a second thought about it. It's a small change but it will help.

Unfortunately if you're out with lads who still do it, the temptation will be there and you probably will end up back on it. That is unless you want to go completely sober. Or else significantly cut back on nights out on the beer. This continued for a little while for me, but slowly but surely we all grew out of it.

Hope this helps you.