Mistress Cloe had an issue with her husband and she made sure that the guy learned never to disturb her or to do anything that she did not approve of. She used her pony play fetish to do this and the guy learned his lesson the hard way. When her friend found her doing that to her husband, she also wanted the husband to experience the same so she did the same to her husband too.
These mistresses wanted to punish their slaves because they had been taking advantage of them and not doing what they were supposed to do. The mistresses had to find a way to deal with them and that is when they came across pony play fetish and they used it to dominate the losers as well as torture them. That is how the slaves learned to change and to avoid pissing the mistresses off.