Mistress Desi had to express her dissatisfaction with how this guy behaved and she did it to make sure that the guy learned his lesson and that he never messed with her again. He never believed that he could be found out but she found out and she had to punish him for it. That is why she did what she had to do and it was fun for her but not for him.
Mistress Jenny is not your average girl. She likes to punish slaves when they mess up and she is a cruel person so the punishments are always painful. That is what she did to this loser today and he cried and begged her for mercy. She forced him to lick the soles of her boots before she trampled him. She made sure he had learned his lesson before she let him go.