Yeah, I had some pretty wank-bangable teachers in School. But I kept my dick under control and I think I've come out with good grades. How can you not make eye contact with her? How guilty do you even feel? You only fapped to her, its not like you made a choice which will define life and death. In all of the years of your life, you spend a few minutes or even hours fapping. If you don't tell anyone, its fine. Get over it.