Mistress Meg and her friend mistress Misty had a bet with this guy. He thought he was smart enough to outwit them but he did not. They won the bet and they chose to humiliate him as a way to redeem it. They rode him like a pony and enjoyed how he struggled to carry them. They did it for hours till he could not manage to support them however much they whipped him.
Mistress Joss and her friend mistress Misty tried to ignore this guy but he could not allow them to ignore him. He insisted on keeping them company and when the mistresses went home, he followed them. The mistresses did not object since they wanted to try pony play training on a loser and he had presented himself. They had fun riding his back like a pony and doing it at the same time which made it worse.
Mistress Joss, Meg, and Daria wanted this loser to do as they instructed him. He did not and had to pay for it. He regretted not doing what they wanted as the three mistresses rode his back like a pony. They did it at the same time and made it very painful and exhausting for him. He tried to beg them to forgive him but the mistresses ignored him and went on having fun.
When this mistress realized that this loser was not going to grant her wishes, she had to make her do it by force. She called her best friend and since they did everything together, they tortured this girl together too. The mistresses rode her like a human pony and they even pony trained her. They slapped her and even rode her together. It was painful but they felt she deserved it.
This slave was slow and his mistress was fed up with trying to make him change. She did not want to keep telling him things which he could not do. She instead chose to trample him. She called her friends and the mistresses turned him into their human pony. They all rode him at the same time and nearly broke his back as they did so. They prohibited him from lying down despite being tired.