Mistress Valentina had tried her best to get to this slave but she could not. She had to resort to some extreme measures to get to him. That is why she chose to use her shit fetish to do it. He was turned into a toilet slave and had to feed on poo before he got the message she was trying to pass across to him. He never forgot it.
Mistress Valentina wanted to dominate this guy and she did it in a way that this guy had never seen or experienced before. That is why she chose to use her shit fetish to teach him a lesson. The poor guy had to eat her shit and he also had to drink her pee before she was done with him. He learned his lesson the hard way and never failed to cooperate with her again.
Mistress Valentina was out to scare this guy and she did it with her shit fetish. She did not have any issue with this guy but she wanted to scare the shit out of him so that he would never want to piss her off or mess with her. That is exactly what the mistress did and that is how he learned his lesson the hard way and he changed.