From what I think, you're trying to map the idea of rap music into the classroom setting using rap terminology. So you're playing on our expectations of what normally happens in a classroom and replacing it with instances of rap. I can see how you're using common class events that people can relate to, "student complaining about the tedium of x" --> "Teacher responds with an explanation of the usefulness of x"
It is tricky to continue from here. In the first three lines, you're essentially doing a mapping scene from rap into school, plus an alternate reality scene where the students accept that it is indeed normal to be learning rap at school. I.e Rap is taught at school.
i.e from the student's first response to the teacher "But sir Gangster rap is so boring..."
Okay so there's the first 3 lines. It clearly shows how the scene will develop. Teacher will use some common phrases in the classroom replaced with rap, student will then behave like a typical student being bored with school work.
Then in the very last lines spoken by the Teacher, it's also apparent that in this alternate reality, there is a straight vs absurd scene developing. This is because the teacher is no longer behaving in a way that we can relate to teachers i.e getting students to disrespect the teacher. That is something weird so it makes the teacher become an absurd character, so now you're trying to get the student to straightman the scene by pointing out the absurdity of the teacher.
So I think the difficulty here is balancing between making the teacher absurd i.e getting student to swear at the them, and making the teacher behave in a way people can relate to i.e just saying things that teachers would say typically.
So I think what would be easier for you is instead of making the teacher absurd, keep it a mapping scene where the teacher says typical things teacher would say and replace that with rap terminology while students keeps behaving like a student and pointing out the inherently unmoral nature of rappers and rap music through using typical classroom situations like student not doing his homework, student thinks subject is boring, student gets grounded, student is talking too loudly and pepper in the rap.
What would also help is developing on why the teacher is so passionate about rap, what is it it about rap that the teacher likes so much even though its sexist