Lady Scarlet realized early on that her professor was biased against her but she never got to know why. She did her best to pass the unit and to graduate with honors. But she never forgot what he made her go through and she had to teach him a lesson he had never been taught before. The mistress cruelly used her shit to teach him a lesson for the benefit of the other students coming after her.
Lady Scarlet was collaborating with this guy on a project but he was lazy and she did not like him to continue with his laziness as it was affecting the work she was doing. So she had to do something about it and that is why she chose to use her shit on him. As he ate her shit, he realized she was not messing around and he changed like she wanted.
Lady Scarlet is a gorgeous girl and she loves to control guys and make them do naughty and nasty things for her own fun and enjoyment. That is why she chose to make this particular guy eat her shit. The mistress could not believe the sort of hold she had on him and so she asked him to lie down and he did. She then facesat on him a little and he loved it. Then she unleashed her shit on him. He was shocked but he did not do anything. He just ate it.