To the OP: maybe you can answer me this question.
You say you're straight, and I'm happy to believe you, but the fact remains you're sucking a dick, regardless whose it is, and that to me is a gay thing.
If you're straight, presumably sucking a dick would not occur to you, but obviously it did. Probably just in a "i wonder if i can do this? Oooh, i can!" kind of way. It's a more elaborate way of jerking off really, i suppose. But still, you're sucking a dick. Do you get my point? not sure if i'm explaining myself well.
Please don't take this as me attacking or questioning your sexuality. I'm just genuinely curious as to how this all works out in your head.