Mistress Natasha did not like how much her husband masturbated. She wanted him to learn how wrong it was and stop it. But he ignored all her warnings and she had to do something different to show him how serious she was. She hand trampled his fingers and his hands so that the next time he felt like jerking off, he would hesitate because of the pain he felt as she did it with her heels.
Cassi is a simple mistress. She likes to give simple and clear instructions and if you ignore them, you do it at your own peril. She also lets the slave know what the consequences of his actions are. This slave tried to test her to see if she could go ahead with her threats and he lived to regret it. She trampled him on the head and mouth and finished with his hands.