Call him and confront him.

Call and say: "Hey, we gotta talk about what happened, come on, we've been friends for years, we should talk this out instead of avoiding eachother. Let's just go grab a coffee or something".

Then in person be blunt and straightforward, say, "hey I know it may be awkward. I know we were drunk, but I honestly had a good time and depending on how you feel I'd be interested in maybe fooling around again sometime. Im honestly not interested in dating you, but I absolutely want to stay friends. So if you want to backtrack and forget about it, we can do just that and leave it behind as if it never happened. It's up to what you on what you want to do".