I'm a straight guy, so I don't know from experience. However, a bi friend told me the other day that there is a significant difference in feeling between men's and women's asses. Can those who have gone both ways share your thoughts on this? And if there is a difference, what causes that?
I suppose that depends on whether you mean it from the giving or receiving aspect. If you mean from the receiving point of view, then what a man feels is certainly different from what a woman feels as with the man the primary source of stimulation is the prostate gland, which women don't have. If you mean from the giving point of view, then I have found it easier to penetrate women anally than men. Other than the simple possibility of this being nothing but co-incidence, my only explanation is that it's a result of the difference in the shape of the hip bone - the female hip is wider to allow for pregnancy & childbirth. As far as the sensations for the giver are concerned, quite frankly I've not found any difference. Once penetrated everything is physically exactly the same - with the rectal muscles squeezing along the penile shaft it makes no difference whether the rectum is that of a male or a female - after all, when it all boils down to it, it's nothing but a hole.
I've heard this before, a bi-sexual friend said something like woman's asses are tighter at the base of your penis, but wider the farther in you are, and men are the opposite, or something, I can't really remember what he said.