My T knows I often have a beer before session and is OK with it. I have a pretty high tolerance, and it's one beer, so it doesn't actually affect me much. It's really more a psychological thing at this point--he and I were just discussing that Monday, in fact (it started when I'd had a panic attack in session with ex-T and another with ex-MC, and that felt sort of like a waste of a session, because they spent their time calming me down, so it was like, "Well, if I have a drink, maybe I won't have a panic attack." It's likely more a placebo effect at this point). I think he did say once not to show up drunk, which I wouldn't. I'd be too worried about the lack of inhibition and saying something I'd regret. Plus if I was really drunk, it would likely waste the session. (I would be curious to see what my T is like when he's drunk, but that's a completely different thing...)