Like Ra's Naughty Forum

Here’s another... [WARNING! Experienced ass-players ONLY!]

1. You’re forced to crouch above the depicted plug.
   
2. Surrounding the base of the plug is a pressure plate which will unlock your restraints when sat upon.
   
3. Your ankles and hips are locked such that you can only raise or lower yourself.
   
4. Your arms are locked to a bar in front of you so you can steady yourself.
   
5. A button near one hand will provide a squirt of fresh lube from below whenever desired.
   

[attachment=31358]

Good luck... 😁

Or this one: https://www.likera.com/blog/wp/archives/14339

... too dangerous ... I tried once to go an extra pare of mm ... Very painful ... And might cause serious damage.

I added a warning. Mostly fantasy scenario however!