Mistress Mia was so pissed at the way this guy ignored her and she knew that if she did not teach him never to do that again, he would keep doing it. So she made him her shit slave and he was forced to do what she wanted. The guy was degraded but he admired her hot and sexy ass on his face even if it was shitting on her.
Mistress Mia likes to prove herself. Whenever someone doubts what she is able to do, the mistress likes to use whatever means she can to prove to that person that she is not what that person thinks she is. And this guy had the unfortunate honor of being disproved using shit. She made him her human toilet and he had to eat her shit and drink her pee. He wished he had not doubted her.