I think that the other main philosophy behind BDSM activities is vastly under-rated but allows for some of the more extreme forms of kink to happen. RACK. Risk Aware Consensual Kink. "Risk Aware" indicating that, while the activity may not be safe or particularly sane, but both parties are aware of the risks involved and have consented to take part. As far as interesting devices, I have always found that the simplist things can be the most effective. Such as making a sub/slave kneel on rice on a tile or hard wood floor.