This mistress felt that this guy had some bad behaviors that needed to be stopped. The mistress knew that there was no better time for the guy to stop them than today and that is why she forced him to do it. But since he was not willing to stop them on his own, she had to make him do it. She did this by forcing him to endure nipple torture and she threatened ball torture too.
When this mistress found out that a serious mistake had been committed, she had to get to the bottom of it. When she narrowed down to the guy, she did not want to waste time and wanted to know what he had done. He did not want to talk but since she knew it was him, she chose to punch and torture his nipples to make him confess. He did after that.