Interesting, but it doesn't sound like a 'problem' per se. As long as people don't do these things against their wishes. It's not a bad thing if people broaden their sexual horizons IMO (though some of the sexual acts in porn are a bit gratuitous). But I strongly believe what consenting adults do in the bedroom is their business and nobody else's.

And it does sound like it's definitely a subset of the more mainstream porn that he's practicing, after all the more extreme things often require more people.

Like the other poster I also wonder whether this is a result of influencing from porn or that porn is influenced by changing behaviour. After all, porn wouldn't be made if people didn't like it.