I'm thinking of holding the student after class so that I can belittle him in private.
What do you plan on doing to them?
It's not a secret that he is a bad student. So I will punish him by insulting him in private to get better results from him.
It is wrong to belittle students. You should focus on trying to help them do better in your class and teach them.
You are not understanding that I am trying to help him so he can be better.
Maybe your intentions are well but this is not a way to improve their performance, in fact it's counterproductive. Instead try to talk to him in a kind manner and understand what causing them doing bad at school.