>>>So no one else can tell me?
No way of knowing, especially from the limited information you gave us. Even if you gave us an entire history of everything that's turned you on (and hasn't turned you on), I don't know if we'd have a perfectly clear idea what's going on.
You're getting off on the idea of giving oral to guys. Does that make you gay? Not necessarily. I've gotten off to fantasies of sex with guys, women, groups, famous people, utter strangers, aliens and monsters...but I don't think I'd actually want to have sex with all of them.

I've had fantasies (and not just sexual ones) about being and doing simple, complex, normal and outlandish things. That doesn't mean I necessarily want them to come true. It's fun to fantasize about being a rock star, say, standing on stage and facing the adoration of thousands of screaming fans...without actually having to learn an instrument, write a hit song, and play in crappy bars for four years. As one famous singer once told me, "I never fantasized about the long trips in the van, or facing yet another fruit tray." That's reality. The fantasy has all the positives you want, without facing any of the negatives that come along with it.
So back to you. Does this mean you really want to have sex with a guy? Offhand, I'd say no. Why? Because you lose interest completely post-orgasm. You don't sit there in post-orgasmic bliss thinking "Yeah, that WOULD be hot". Instead, you feel "disgusting" and "dirty".
And that, I think, is probably what's going on. What's getting you off isn't the cock, per se. It's the whole "disgusting" and "dirty" thing. It's exciting to fantasize about crossing borders from time to time. Doing things we wouldn't normally do. I think that's all you're doing, and it's fine. Enjoy it. Eventually, the fantasy probably won't hold the appeal it once did, and you'll find another one to take its place.
Lex