Lady Karame felt that this student was dragging others behind. He was slow and that made it hard for her to go at a faster pace. That was because she did not want to leave anyone behind. She felt he was slow because he did not try harder so she trampled him with her sneakers in an effort to make him apply himself and try harder to study and be a good student.
Lady Karame does not like cowards and this guy was one. She did not know what to do with him so she thought about it and she chose to trample him. The mistress did this using her sneaker trampling fetish. The mistress made it very painful for her and she told him it was to toughen him up and make him become the kind of guy who was not afraid of everything.