Princess Serena wanted to tease this loser and that is what she did to him. He had info she wanted and she knew the best way to get it was when he did not have total control over himself. She teased him and got control over him and she made him tell her everything that he knew. And when she had gotten all info from him, she made it look like she had had a good time with her.
Princess Serena sat on this loser's face and farted on him. She did so for fun knowing that he could do nothing about it. She wanted to humiliate him for being forgetful. She felt that if she humiliated him, he would try hard not to be humiliated again and that would lead to him not being as forgetful as he is currently. And it actually worked as he did all he could to remember things.
Princess Serena did not want her slave to forget the kind of punishment she can give if he messed up. So she punished him without him doing anything. She was doing it as a reminder to him of what she is capable of. She crushed his face with her ass and she also facesat on him and had him lick and smell her ass as well as her farts. It was disgusting and degrading.
Princess Serena wanted something from this guy. She knew he had a thing for her ass. So she used her ass to humiliate him. She made him lick her ass as she facesat on him. She also had him lick her pussy over his clothes just to fool him. She got all the info from him without him knowing and humiliated him for fun and when she had had enough she let him go.