I read a story once about a male slave that was being trained as a pony boy. His owner wanted perfect high step, perfect motion, perfect response to commands.

As the story went, it took a lot of training to get it right. The pony boy slave was tacked up in his pony gear, but then hooked to a pole to do some lunges (basically trot in a circle around the pole). There were various sensors in place that measured his speed, the height at which he lifted his knees, etc.

At first, his human trainer Domme would work the machine. It would yell out various commands which the pony would have to obey, or an automatic whip would whip his ass. The machine would measure the pony's reaction to each command, and whip him for every incorrect move.

Eventually, the trainer Domme would get bored or something, and just set the machine on autopilot. The Domme could leave the pony in the machine for hours to help reinforce his training. She could come and go as she pleased.