Bondage wheel
From wipipedia.org
A bondage wheel is one of the largest (and most expensive) pieces of SM equipment found in a Dungeon. It consists of a large vertically mounted, rotating wheel to which the victim is strapped to. In this respect it is similar to a St Andrews cross, the victim can either be strapped facing the wheel (suitable for whipping) or facing out (for genital torture). The difference is the bondage wheel can be rotated allowing the victim to be turned upside down.
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