For me the very first time hurt like hell. My legs ached and shook for days afterwards, but the act of doing it was hyper-erotic. The best I have had was a French guy who was average in size, uncircumcised, and who took it very very slowly! The first stage of penetration has never appealed to me except if I can see it happen to me, but once past that and past that second stage, the feeling of a penis sliding into me is without any kind of equal. When the Frenchman - Rene believe it or not - came, he did so leaving a lot of sperm. While I could not feel it inside me, I sure as hell could feel it coming out. That feeling was heaven. With Rene I achieved and anal orgasm just once though we had sex anally at least once and twice a week over some time. His sex drive was endless.
The first serious anal orgasms I had were provided by two men who each took a turn with me. They were both attorneys and life-partners. I knew they were gay - it was very obvious - and one of them asked me if I had ever had sex with another man. I lied and told him no. It was the seventies, so no harm no foul back then. He asked if I would like to try it and I told him that yes, I would. I went with them to their place where we all engaged in oral sex over a long period. One of them, Ben, came almost as soon as I took him into my mouth. The other, Simon, took almost fifteen minutes before he came.
The three of us went out to dinner at a nice place nearby before going back to their place again. Simon had been apologizing for taking so long to reach orgasm the first time. I didn't care, his penis was similar in size to mine, circumcised, and I just wanted it again no matter what. While I was going down on him he asked me if he could fuck me. I was eager to please and said "YES!"
To enter me he had me lie face down and he entered pretty quickly. After three or four thrusts I came, and I think that made him come too. Ben fucked me immediately after Simon and it took him a long time. I came, I think, three or four times before he did.
If I could believe it was safe to do so and had the right partner, I would do it every day. For me anal sex is just incredible! I love it!