Is this shit popular in the US(there seem to be at least enough people into it to maintain a subreddit)?
In the US, I don't think it's that common.
Or at least I hope not.
I don't even think there's a legal way to get a doctor to perform it, since it really doesn't have any medical benefits. Most times you're literally tearing up the urethra and the head of the dick.
Or all of the dick in extreme cases.
Or whatever the fuck happened in this specific Reddit case.
It's considered an 'extreme body mod' and I think how people do it in the US are at-home via online sources or through more underground "if you know a guy" situations.
Possible some piercing and tattoo shops, but even then, it's really too far out there and maybe too niche for it to be openly sold as a service by professionals (if they value having a business license lol)
At least I hope it's not common because now I'm worried if I meet a guy, hit it off with him and then he's already got his dick fucked up like that.
Outside of this weird hobby, it's only done by some Aboriginal Aussies, South American tribes, and African tribes from what I gather. It seems to be a bizarre version of circumcision for these cultures.
Regarding the reddit aspect:
it's Reddit… I'm sure there's some people that genuinely get off on the idea of sleeping with someone with a mangled cock, or get off on the idea of doing it to themselves, or even get off on the idea of
making someone mangle their own dick. (There are plenty post-SRS subreddits out there, after all.)
But what I've learned from Reddit, just because there's an audience for an extremely fucked up and niche kink, doesn't mean everyone who enjoys it makes it happen irl.
For example of a similar instance of that happening online: the infamous Cannibal Cafe / Armin Meiwes case. Armin Meiwes confessed that he talked about his cannibalism fetish online with plenty of people and these people also had the curiosity/fetish.
But when it came down to actually indulging irl? Only one out of the hundreds he reported chatting with took up his offer.