Lady Krasaviza used her skates to crush her slave's body. She realized he was developing tolerance for the kinds of punishment she used on him. She did not want to be rendered impotent so she changed tact and she used her skates to trample him. They were more painful and he learned his lesson the hard way and since then, he as never tried to go against any of her wishes.
Mistress Lisa wanted to trample her slave as painfully as she could. She thought long and hard about it and she decided to trample him using her skates. She made it as painful as she could and he begged her to forgive him but she did not listen. She wanted him to learn and he learned the hard way. From the on, he never did anything to piss her off.
There is no excuse for being a bad slave. And Miss Jessie makes no exceptions for anyone - her bloody pooch lies down on the floor while she starts trampling him hard all over his naked, fat body. She uses her full weight and tramples over all his extremities, which makes him nearly cry like a school girl! Then she stomps on his balls and cock, they're useless anyway!