Does it need to be "labeled"? Maybe in a certain mood, a "straight" guy might have some sensual fantasies, or see a penis, here, and get hard, and have no idea why!?
Fantasy is a wonderful thing, in that you can now see images and chat with people, but you are a thousand miles apart, and maybe it is easier to explore some latent feelings, ideas, or fantasies, online, with someone.
I think the internet, and sites like this allow people to explore, in an anonymous way, things they might be terrified to do, in person.
I think that I can come to this site, and some images of some penises make me aroused, and I don't know why, but I am not afraid of that feeling, as I don't think that there is anything wrong with being "Bi" or "Gay".
Personally, I see myself with a woman, in an intimate relationship, but with the changing times, is there something like a "boy's night" when I can just accept that I get a little turned on, by a penis? Maybe she feels something similar, liking women? But we are still heterosexual, and a couple. Some new Paradigm, maybe?