An amendment: as much as I love getting fucked (and rimmed!) by a man, I never wanted to fuck or rim one. But I would be overjoyed to do any & everything to a gorgeous shemale's ass that she would LET me do, very much including rimming AND fucking!
I have recently with our present lover. He's the only man I've rimmed and his wife's ass is a total joy to rim before sliding my cock inside it.
With either a woman or a man, their asshole is going to have to be CLEAN before I put my tongue on it, it's a big turn on for me with a girl, can't see why it wouldn't be the same with a guy...