IRL, that would likely explain such a *cough-cough* escalation of her class's overall performance. Alas, there seems to be no evidence of that happening, so for now, chalk it all up to Hentai Logic (or something).
Well hey, anyone can achieve amazing things with the correct 'motivation' and 'reward'...Quite a foolproof method, really.
Touching breasts is one thing, but when sex is on the table...Well, surely this was the only possible result, yes?
But hey, considering that ending, I'm sure it's a win-win for all involved. She enjoys it and also gets praise for having a successful class, and the students get good grades for their reports and also sex.
In the news you always hear how a teacher had sex with a student. Some exceptions the kid told on the teacher. Now if your a girl I understand but if your a boy and you told. I was like why would you tell? You lucky bastard!!!! I wish my class teacher said we could fuck her if we got good grades. I would of been the class Victorian.