My best friend came onto me yesterday.

For clarity: yes, I do mean my same-sex best friend.We were all drinking for my birthday and eventually everyone went home. Well, we're shitfaced and he says that he wants to suck my dick. I shoot him down, even though I am massively aroused when he brings it up. He knows I'm aroused (visible,) but accepts the rejection.I went through the rest of the night like that didn't happen. Now it's the next day, and I'm filled with a lot of weird feelings. I don't want my platonic best friendship to turn into a gay relationship, or even into a gay sexual fling. We were always "bromantic," but this is different. I feel a little uncomfortable now. Like I can't be faux-flirty like I was, or ironically physical, or any of that. Now it's real and I'm frightened.One of the problems is that I was, and am, still turned on by the idea. Not to be TMI but I've been masturbating like crazy since last night, like every couple hours, virgin-after-sex style masturbating. I always considered myself very sexually open and everything, but I did think I was heterosexual. Now I don't know. I feel kind of ashamed, despite how cliche that is.This is seriously really weird for me, so if you guys have any other subs I could post this, I'd appreciate it. To cut to the chase: no, I really sincerely do not want to make anything out of the attraction. I've avoided sex with female friends, on the basis of keeping a friendship, and I guess I'll avoid it with boys too. I just kinda want to talk it out right now.