I enjoy league, and I enjoy alcohol. And I enjoy mixing them. Like Winston Churchill said, I've taken more out of alcohol (and league) than alcohol (and league) have taken out of me.
One or two drinks can be very relaxing, and what it will cost you in reaction time might be made up in anxiety reduction. It's the same reason most of the guys I go bowling with tend to bowl better after a couple of beers.
There's a difference between having a couple of drinks and playing while drunk/hammered/smashed.
I've played while drunk. It's fun!
I wouldn't play ranked that way. That's just not fair to people trying to climb. You need all your faculties.
Co-op vs AI, customs with friends, even ARAM. Normal blind/draft if I'm part of a 4-5 summoner pre-made. :)
And for the love of god, don't go announcing to everyone that you're "Drunk AF".