This couple drinks what I would consider well within normal for people. They have a drink or two during the week a couple times a week; more on weekends, and they do it together. They don't get falling down drunk or blackout or anything like that, but it does clearly lower their inhibitions, which could cause them to do things they may later regret (I think). Their pot use, I would guess, is once or maybe twice a month. Although we have no moral or ethical problems with people who use alcohol or marijuana reasonable, everyone in our poly family doesn't drink, other than sipping less than one drink to be social (you can't always get NA beer or grape juice). Our reasons vary, but the primary one is that we all want to be in control of ourselves, others are sleepiness, headaches, loss of a perceptual "edge." We are admittedly the non-normal ones in this. None of us remotely likes the idea of using drugs.
Red and I found what we did to be fun and would like to explore it with them more. They are physically/sexually nice, but Red and I don't find them attractive enough in all respects to be thinking that we want to have full intercorse swap with them, or even play that leads to orgasming. Our concern is that exploring soft swap with them will either: a) go to far for them (I was worried that Red seeing her exposed tits may have upset him; it didn't) and lead to regrets after the buzz wore off, or b) set them up to think there will be more than Red and I are willing to do, disappointing their their expectations. As I have previously said, I called her up the day after to tell her that we had a great time (reassuring her there were no regrets on our part), and to assess his and her feeling by asking a couple questions ("I hope you did mind that I let him touch my tits?" "He was OK with Red seeing your breasts?") So for now it seems OK. Communicate and move cautiously.