Madame Marissa was interested in shutting up this slave. He talked a lot and she did not like that. She had talked to him about it but he did not keep quiet. He had to learn his lesson and that is why she used her hand over mouth fetish to punish him. As he choked a little, he realized how serious she was and he panicked and peed his pants. But he stopped and never repeated that mistake.
Lady Phoenix loves to dominate people for fun and that is what she did to this guy today. The mistress ensured that she choked him for her own fun but also to teach her friend how to do it. In addition, she managed to scare the shit out of the guy and as a result, knew that he would never disobey her. So it was a great win for her.