This guy was insatiable and mistress Alessa was tired of having sex with him. It was becoming boring now as he wanted it all the time. So she had to make sure that she dominated the guy and that she degraded him like he needed to be degraded. She used her fisting to make him learn that he had to tame his urges. The pain he felt as she double fisted him made him change and contain his urges.
Mistress Alessa was not happy with the way in which this guy did his things and she had to punish him for it. She chose to fist the shit out of him and she made sure that he learned his lesson the hard way. He cried at what she did to him and it was super painful. He never repeated what he had done to piss them off and they never tortured him again.