Mistress Ann does not like stubborn people and when she realized that this guy was one, she tried to talk him out of it. But the guy did not do what she had asked him. In fact, he doubled down and she did not like that at all. That is why she opted to shit on him and she made sure that he ate her poo and that he drank her pee as punishment. He was never stubborn with her again.
When mistress Ann jerked off this guy and she got naughty with him, he mistakenly thought that she was into him and that she wanted to get freaky with him. That is why it came as a huge shock to him when the mistress forced him to eat her shit and drink her pee shortly after she was done making him enjoy her hands on his dick. He slapped himself for not seeing it coming.