While I am not terribly happy with my body image (have a lot of weight I need to drop), I have been told by several ladies that I have a really cute ass. OK, as long as they are happy. LOL.
I prefer to go commando, just for comfort, but, when I wear underwear it is; Low/NoShow brief, Bikini or Thong. Yep...a big guy in a thong. Well, I don't wear it for appearance or show off. Only person likely to know is the woman that I am with. So, by the time she knows I'm wearing a thong we are taking it off anyway. The point is, I find them very comfortable. Well, I don't wear them if they aren't comfortable. LOL. Different brands fit differently. Not all are created equal.
So, unless you are talking about a thong in public (like a swimsuit) I really don't think anyone should blanket say...."Not on a man". My underwear is mine. I wear it for comfort, fit, modesty (whatever)....it is not an advertisment of some sort. If I were out in pubic in my underwear, then it would not be a thong. LOL.
Just my $.02