Lady Scarlet and mistress Gaia are sadists. They love to dominate and degrade mostly for fun and that is what they did today. It was a lot of fun for them and they made sure that this guy was not just humiliated, but that he was also scared shitless. They fed him poop and trampled him a little before they were done with him. He never messed up again with them.
Lady Scarlet was interested in degrading this slave and she did so using her high heels. The mistress made sure that he was tied up and he was in a lot of pain. But that was not all as the mistress also made sure that he ate her poo. He had to eat it all as well as drink her pee before she felt that she had done enough to him.
Lady Scarlet had an issue with this guy and she punished him for it. But she was not satisfied with the kind of punishment she had given him and she had to find something else to give to him so that he would never be tempted to mess with her again. That is how she cruelly turned him into a human toilet and made him eat her shit. The punishment worked.
Lady Scarlet felt that eating shit was one of the necessary skills that her slave needed to learn. And she made sure he learned those skills. The mistress loved to punish losers by making them eat her poo and that is why she wanted this slave to learn those skills. So she waited until he had messed up before she made him eat her poo and he had to do it.