Hey furfan,

I had the pleasure of experiencing that gag while sessioning with MTO. I am a huge bondage lover and of course MTO is an incredibly talented and extremely well equipped bondage expert. I was standing upright in a very severe bondage hood and some other gear when she inserted the gag into my mouth and then attached the gag to the the the locking piece that had been attached to a beam that was part of her very elaborate bondage rig. It wasn't until I tired to turn my head did I become aware that it was now impossible for me to move my head in any direction up, down or sideways. I was in that position for some time and it became uncomfortably challenging, as MTO intended.

MTO also has this gag,

https://www.meo.de/en/mouth-gag-muzzle/3382-silentium-tongue-gag-lip-gag-ref-8408-00.html#

I think that gag would be one of the more extreme although I have not yet experienced it.