Surprisingly enough, I just don't like looking at dick pics. They're just ugly to me.
I've liked looking through skimpy swimwear & exoticwear online catalogs, but mainly to imagine what it would be like to wear something like that myself. I don't even need to see anything above the waist.
One of my ex's (who turned out to be gay, or bi, herself) friends (he's gay) said this about me after meeting at a cookout -- "He's so sweet, and so nice, but sooooooo straight!"
I joke, partly, that I'm lucky that I can turn myself on just enough to masturbate. The thought of being in a sexual environment with another male participant makes me flaccid, quicker than thinking of a naked grandma.
After saying all of that, I feel like I have to clarify that I just don't give a shit anymore. Gay, straight, whatever. There are hetero couples who do things that I can't imagine enjoying myself, too.