The Berkeley Horse

A contraption named after it's inventor, Mrs Theresa Berkeley. It was acclaimed as a wonderful 'machine' back in the late 1800's when the birch was king. The victim, naked of course, would be strapped to the horse and with the cut out panels, the genitalia would be totally accessible. Accounts talk of ladies sitting in front of the male victim, who would 'manualise his embolon' whilst the birch was sadistically applied. There is an account of one victim willing to pay a rising fee if he is flayed to increasing levels of suffering e.g. blood is drawn, blood trickles to the floor. What puzzles me is that in 40 years of experience never have I seen such a device in real life.
I know in the 70's it was illegal to have two Mistresses at play as this constituted a brothel, so a bircher and a 'manualiser' wasn't easy to find.