I simply have to start with the Spanish Pony! The Spanish pony is one of my favourite tools. It is simple, yet diabolical and really makes a sub obedient to the Master. The most simple of dungeon furnitures it tames even the most bratty of submissives, especially where the upper part of the body is restrained.
You can see from the gallery that there are very portable versions to fully scoped dungeon-mounted versions and that you can be even more monstrous to your sub by building is a raked upper bar or by adding a metal strip allowing you to give your submissive electric shocks. (My dungeon version has a switch mounted to the footplate, so that as soon as my dearly beloved sub steps on the plate to take the weight off her aching pussy, she connects the circuit this giving her a shock through both her feet and her thighs, which repeats every 15 seconds. ……and if she thinks she’s sitting comfortably, I’ll come along with the magic wand and inject a little shock down the metal edge and through her pussy. (Plus the metal bar is usually very cold, which is an additional punishment).