When Mistress Dorothy found her slave smoking in her house after she had forbidden him from doing it, she made him feel the consequences of doing it. She wanted to teach him that choices have consequences. She trampled the mouth that smokes by inserting her foot in his mouth and having him lick it despite the fact that her feet were dirty and sweaty as well as stinky. He learned his lesson.
Princess Cera knew that she had a certain power of this guy and she used it to her advantage. She did not even feel guilty. It was fun and interesting and she did not have to break a sweat while doing it. She made the guy lick her feet when they were sweaty and stinky because she lied to him that it turned her on when he did that so he licked them.