Mistress Gaia, mistress Scarlet and mistress Tatjana needed to find out what this guy's pain threshold was. So they chose to use their ballbusting to do it. The guy was stripped naked and he was kicked in the balls. The mistresses did it as hard as they could and they laughed at him as he cried and begged them for mercy. The mistresses knew that he had a low pain threshold and was not a good fit for the role they wanted.