Such a kind of books are good materials to learn another language.

I guess "You(the teacher) are the best source of porn for me(the girl)." is correct.

And...
ずり came from せんずり that means masturbation.
ねた means material.
So, what the girl really want to say is "I masturbate you".
I've never use this verb in English. I don't know this is correct way to use this verb.