I'm a guy, and I've got a fetish for male monsters...
Irl, I'm not exactly vanilla, but I like to be in control, but I won't do things like scat/piss, or blood (though I do love being bitten and scratched)
But fantasy-wise, I'd love to have a monster lover, something strong, muscled, dominating. Controlling me and making me his slave, as he either fucks me relentlessly until he's pleased, maybe digging his claws further in my flesh so blood draws, lapping up the blood, or sinking it's fangs and having it fill and finally drenches me in cum, inside and out.
Though I think I'm a rarity, even on /g/ only gay guy that's into /f/ or /g/ related things if it involves m, or m/m. But it's kind of fun in a way to basically say that gay guys can have odd fantasies too. Well, odd to others normal on here.