Mistress Valentina did not like how bothersome this slave was and she had to punish him for it. She felt that if she did not do anything, he would be emboldened and she did not want that. She had to dominate him and she had to torture him which she did without caring about what he felt. It was super fun for her and she loved everything and how it happened.
Mistress Valentina did not want this bully to continue doing what he was used to doing and she had to put a stop to it. That is why she chose to use her femdom ballbusting fetish to dominate and to teach this guy a lesson. He never saw it coming and he wished that he did not have to do it but there was nothing he could do about it.