I was 11, in the 6th grade. I became friends with this guy Tony. I thought he was amazing. He was older than i was. We would go over to his house after schooland hang out until his parents got home. I really just wanted to be friends, but one thing lead to another. One day he decided we should do it. He was very gently, and didnt hurt me that much. Once he started pumping, i knew he was really liking it. It wasnt long and he was done. It made me feel sexy to make him happy but i didnt care either way. We did it ever day after that. Sometimes i would watch TV while he plowed me Doggie style. It was with another guy that it became good for me.
It was my wife, who was then my girlfriend, who initiated our first anal sex session together. We were naked after a night out and I was about to fuck her pussy as she bent over her sofa. I rubbed my cock all over her arse, which I had done on many occasions, and she uttered the words which I will never forget- "you can put it up there if you want!" It was like my birthday and Christmas rolled into one. I fucked her twice in the arse that first night, each time without lube, and it felt fantastic. We have anal sex occasionally nowadays but I don't think we will ever surpass that first time for the sheer naughtiness of it all. We were both anal virgins until that night!
I've had anal sex with women exactly 3 times. My first experience was consentual, we rushed it and she was in much pain. The second time was with a girl I ended up staying with too long, I was actually on the phone when she backed her ass on to me, without getting graphic, she was not empty and it sucked. The 3rd time was with my wife, I was drunk... had no idea I was in her ass until she told me long long after.
I initiated my first anal experience on myself so long ago I can't even remember it, and I've been doing it ever since. With partners, I think I've often brought it up first but most have been receptive to the idea and enjoyed it enough to continue wanting anal and often start asking for it themselves.