Mistress Tiffany wanted this slave to learn to respect her so she did something he did not expect from her. She made him undress and she used her bare hands to crush his nuts. And she also pinched his dick painfully. The slave was shocked by her audacity and he learned to avoid pissing her off as he knew she was capable of doing something painful to him as punishment.
Mistress Tiffany does not tolerate or condone any disobedience from her slave and when this one was disobedient to her, she did not shy away from punishing him. The mistress did it brutally by ball kicking him while he was naked and that is what led to him learning his lesson and not pissing her off again as he knew what to expect if and when he disobeyed mistress Tiffany.