If you’re watching videos and asking yourself how to achieve that: I think they fake it lots of the times. You can use a small hose and hide it. And I think I also read they insert fluid into their private parts with a syringe or something. That obviously comes with major health risks. So don’t do it. But don’t compare yourself to that kind of videos. And I’m not sure if it’s true anyways. I just read it somewhere on the internet.