What is my friend doing????????

Ok, I have a friend who was the first person I told about me coming out of the closet. The reason i picked him of all people to tell first, was because he is my crush, (straight - to my understanding) I haven't told anyone else yet, and its been about 8 months since i told him, although some of my close friends really think i am gay. But im just not ready to come out to everyone. Anyway back to the point, recently my friend that i came out to has got a bit closer to me, he hangs out with me and my good friends, which he wouldn't normally do etc. and in the ped 3 weeks, he has been really subtly flirting with me, and i think he is trying to arouse me a little, he slaps my bum occasionally, he hugs me a lot more than my other friends do, he fell asleep on my lap once. obviously i love this behavior because im gay and i seriously fancy him, but i want to know is he just teasing me or is he interested? The first time i asked him 2 weeks ago "what are you doing", (one of them long drawn out ones, like they are up to something :P) and he gave off a little laugh and said nothing, the next time i asked him "dude, you know i like this , but why are u acting like this" he replied "im just kidding with you" and hugged me from behind and put his arms around my tummy and his head on my shoulder. I've heard in the past that he has had girlfriends and that he is straight, sorry if this is a little long, but i would really appreciate some help with him, about a week ago i came to the conclusion he was teasing me. until we were pretty drunk at a mates birthday party and he started to feel up my trouser leg, and get closer and closer upwards. i of course liked it, but i am still confused at whether he is biual, straight gay or whatever. please help, and thanks for bearing with me reading this :P