(N.S.F.W) Can you explain this experience?

I am referring to anal sex with a woman. I am curious to know what it is like for both parties. When a man is having anal sex with a woman how does he feel and how does the woman feel? Is it painful or is it pleasurable? I have asked a girl to facilitate me before but she refused because she said that it was too painful and that she was not ready. So what is it really like for those of you who have engaged in it?