This. ^ I tried it once (with my DH) some 20 years ago. He didn't coerce me or anything, we both collectively decided to try it. I had to have 4 shots of whiskey, and get quite tipsy, to get enough confidence to do it!!!
I fucking HATED it. As a pp said, it felt like having a shit backwards. Even though I consented and we used lube, I still hurt and ached afterwards, and it felt so weird and horrible. It was about 5 days before I could shit! (Sorry, TMI!)
DH kept saying he was so sorry, as I said it had hurt, but it wasn't his fault. I said I never wanted to do it again, and he was fine with that. He was not bothered.
As @ChickenChop and some other posters have said, I find it very hard to believe that anyone enjoys it, and I think they have been brainwashed. In addition, even if women do consent, and they are not instantly hurt, the long term affects can be dire. They can suffer from anal incontinence, and a slack anus (anal sphincter muscle damage.) Anal sex is a common cause of faecal incontinence.