Personally, I think Americans in general get too hung up on labels with sexuality. I understand because of the politics of it all and the need to define everything, but I was gay for years before I had sex with a woman, and I actually loved pussy a lot more than I thought I would. I fucked a few women, and found that pussy was a lot easier and fun with the right (ei slutty) woman. And I do it again for sure. But the experiences didn't turn me "straight." I'm still primarily turned on by men and identify as gay. The same way, I think straight guys can truly enjoy and get into gay sex, and still be fundamentally straight. If we would ease up on the labels, I think a lot more straight guys would have gay sex - and gay guys would bag a lot more straight dudes! ;-)
I had this one 24 year-old who was for sure straight who I fucked like crazy. He had been using his girlfriend's dildos so much on himself, he was craving the real thing. And the way he got fucked was more in the position and tempo of a woman if that makes sense - you could tell that's how he thought someone got fucked and that he learned it from watching straight porn. Some tranvestites have told me they always top straight guys because they feel more comfortable being fucked by a "girl" and that means they're not gay. And they probably aren't - but why wouldn't straight guys enjoy having their prostrate worked over - they are built the same way as gay men are.
On a side note, with the 24 yo we didn't have any condoms and I said whatever, we can just suck and stuff. He wanted my cock, but insisted on condoms. Finally on his own accord he ended up just sitting on my raw cock with his perfect round white boy bubble butt and I fucked the living daylights out of him in a few positions and he loved it. It was so hot! After he came (he could only cum by watching straight porn), he got really sheepish and almost guilty that we had barebacked - it was obviously his first time doing that. I knew he would be like that after he came, that's why I didn't cum inside him - but believe me, I wanted to! But didn't want to freak him out all in one go since I felt I was lucky to have gotten him as far as barebacking. Never saw him again, but jerked off thinking about saying nothing and just loading his twink ass with my cum ...