I want to know if a friend of mine is gay?

So, first off, I guess I am bi-curious (I am a guy). There is this guy in my school who I am interested in. Him and I are friends basically. We hangout with the same group, and we see each other basically everyday in school. I have a feeling he is gay, or bi. Some of the things he does to drive me to this question are, he slaps my butt every now and then. I do it to him as well, and he blushes and feels flattered. He also hugs me randomly sometimes. And this one particular time, in a pep rally he was sitting with band while I was in the audience. He kept making these gestures as if he was taking his shirt off, and he blew kisses at me. All of those gestures were directed to me, and he told me later on. He also draws penises on random things, and talks about that stuff (gay stuff) like penises, and buttsex. Also, he does have a girlfriend who I think he really likes, but that really means nothing. Regardless, I think he is gay or bi. Tell me what you all think. Do you think he is gay?, bi? what?