Befor I was married I tried to anal every girl I was with. Some were no way at all. Some were ok but be careful, my favorite. Others were like yea let's do it, no challenge.
Married 20+ years. Wife and I tried anal three times, never went well. No problem.
About 5 years ago we got into mfm fun with a guy we know. Started slow, was very awkward. We worked up to getting pretty comfy together. One night he was doing her from behind, he reached for the lube, happened many times. He lubbed up his dick and said they were going to do some back door. I'm thinking she won't go for it. He started to lube her butt hole, slid a finger in and she didn't move. He got lined up and started to push in, I'm thinking she'll pull away but she didn't. He went SLOW, she grunted pretty loud. He slowly slid in and it looked like her eyes were ready to pop out. He got all the way in, did really slow full length pumps, she was really grunting and moaning. He took aboit 10-12 slow pumps then pulled out, she floped onto her belly and said DAMN. We continued our fun like usual.
Next visit just about same deal he lubed up and slowly slid in, she was OK with it. He went slow for awhile then said he was ready, she stayed with it. He unloaded in her, pulled out and she said WOW.
Anal became something they did but usually just for a minute. One night she asked me if I wanted to try. Anal has become a regular part of our sex life. Not always but often. There's been nights him and I have both fucked her butt. She's good with slow and steady but not hard and fast.