I’ve been in one a handful of times. They are fun, quite a mindfuck. Very aptly named as it is a very humbling experience.

I can’t say they are my favorite though. They can be a bit hard to get into. It’s also kind of an awkward position and most of the “action” ends up being behind you in my experience. So it kind of messes up the visual stimulation. I did have one double Domme session years ago where it featured quite prominently and was a total blast.