Well, first, it’s just naturally more pleasurable for men to have anal sex than women because of anatomical differences and the presence of their G-Spot/prostate. So two men having sex has a different pleasure spin on it, to start with, rather than seeing women have anal sex.
Also, it’s just two hot guys fucking. It’s sex. Sex is a turn on. Whether it’s two guys, two girls, guy and girl, two girls one guy, two guys one girl, orgy, whatever! As long as it’s done right and there’s chemistry, there’s intimacy, there’s a feeling of real pleasure taking place…that’s the turn on!
You’re not thinking about anal sex when you see two guys, you’re thinking about how hot they look, how good they’re feeling, the rhythm they have, etc. You’re thinking about the sexual pleasure they’re deriving from it. It doesn’t matter as much HOW they’re getting it, but rather how good they’re making it look.
Sex turns you on. GOOD SEX turns you on even more. Men, women, it doesn’t matter which combination you use, it’s all still sex and if they’re doing it right, it’s fucking hot.