Mistress Elizabeth wanted to pump some sense into this guy and she used her sneakers to dominate as well as to torture him. She wanted to make sure that by the time she was done with him, he had learned to do things the way she was doing them. That is why she opted to use her sneakers to get him to learn what she wanted and from the way she did it, he learned.
This guy did not know how to shut up and this mistress was not ok with that as she found him to be a nuisance. She laughed at him but he mistook it to be that she was laughing with him. She made sure that he cried as she used her sneakers to kick him and to also lick her soles. He was humiliated but he got the message she was sending.
Mistress Viola was broke and she had to make some money. She chose to use her sneakers to do it. So she dominated this guy and she humiliated after he had made a mistake. She was so cruel to him and as he tried to beg her for mercy, she told him that he could buy his won forgiveness and he agreed. That is how she made money from it.
Mistress Viola and mistress Valerie wanted this guy to know his place and that is why they did what they did to him. They chose to trample him and force him to lick the soles of their sneakers. The poor guy analyzed the situation and he realized he was cornered so he cooperated and did what they wanted him to do so as to avoid any issues with the mistresses.