My partner and I have been using a range of home made and commercial crush toys for several years. I always am sub to him in these games.
For my last birthday I was delighted to find he had bought me one of these to play with.
We already had a humbler so I wasn't expecting it to be a whole lot differant.
WOW was I wrong!!!
This is a very hot toy , not only does it allow really intense crushing if you tighten it right up but the fact that it is happening behind you and you can't really see adds a whole extra dimension.
I trust my partner but with this you can really feel that you are about to be crushed to a pulp.
Make sure you trust whoever is tightening it up.