These mistresses had entrusted the care of their horses to this stable hand but the guy did not do his work well. He did not feed them well and on schedule, he did not clean them properly and regularly and he did not even clean the stable as well as he needed to. The pissed mistresses had to make him eat mud and he ate one which was mixed with horse shit.
Goddess Vivienne wanted this guy to stop being a nuisance to her and other girls as he was constantly hitting on them and catcalling them so she took one for the team and she used her riding boots to trample and punish him. This was after she had caged him and made him regret what he had done to them. He promised never to do it again and he kept his promise.
These mistresses wanted to show this guy what the consequences for his actions were. The mistresses had caught him trying to steal from them and he had to face the consequences. He was shocked at what they did. The mistresses used their riding boots and whips to torture him after they had stripped him naked. He could not believe that those cruel things were happening to him but he could not blame anyone.