This is pretty terrible. What has happened here is that this person has had their asshole turned inside out. Not a pretty picture! Anal prolapse is most common in the elderly, mostly in women. It seems to be related to childbirth.
However, it can also be caused by anal sex, but this is not too common. People who work in hospitals, including nurses, say they have seen an increase in anal prolapse cases among gay men in the last decade or so. Nevertheless, it seems that most gay men do not get anal prolapses.
There are partial anal prolapses and there are full anal prolapses. With a partial prolapse, the asshole comes out of the anus, but you can always push it back in. It might come out if you sneeze, etc.
With a full anal prolapse, it won't go back in. Your asshole has basically fallen right the Hell out of your anus and it's not going back in. Surgery is needed to put it back in.
I joined this really sick porn site once for the Hell of it, just because it was totally sick. It was called Rosebutt Board or something like that. The site was all about what they call rosebutts, prolapses and other distended asshole stuff. I really have no interest in this sort of thing to be honest, and I certainly don't want to do this to my body. I just saw the site and I was like, "Wow! This is the sickest site on the Net! I have to join LOL!" I am not sure exactly what a rosebutt is. It might be some sort of a slight or partial prolapse.
It was almost all men on the board, and only a few of them were gay! Quite a few were these sort of masochistic straight men. But after a while, I figured out that some of the "straight" guys were also pretty bisexual.
Some of these guys were dying to get a prolapsed anus! You saw all these posts like, "How do I get a prolapse! I want one so bad!" Then there would be all these responses saying more or less, "Hey, you really don't want one you know. It's actually not a good idea and it can cause medical issues." And the poster would be like, "I don't care! Prolapses are so cool and beautiful! I just have to have one!"
What it boiled down to was that a prolapse was not so easy to acquire. Some of these masochistic guys had understanding girlfriends who were shoving dildos, often fairly large ones, into the guy's asses on a regular basis. The general advice seemed to be that if you stuck a big dildo in your ass for several hours a day for 3-4 years, well, you just might get yourself a brand new prolapse for Christmas!
There were also a lot of links to really sick websites of these crazy female anal freak porn stars who stick large objects up their asses on a regular basis. Some of them have even acquired prolapsed anuses in the process of doing this and now they are using this as a selling point (I am not kidding!) on their websites.
There were also links to videos of female porn stars getting fucked in the ass to the point where their anus prolapses a bit. The girl usually freaks out and shoves it back in her ass. Ava Devine has a funny video of doing exactly this. There was a crazy Russian porn star named Mila Shnegol a while back who was always sticking stuff up her ass, and I think she eventually got a prolapse too.
However, in straight porn, even among females who do anal sex, prolapsed anuses are not common.
Even among gay men, they tend to more a result of such things a fisting (having another guy stick his whole fist up your ass) and sticking very large objects up your ass and less associated with normative anal sex. Fisting and sticking large dildos or other objects up your ass is not recommended but it is quite common among gay men, sadly enough.