If you are underage, you could cost your crush his job and even send him to prison. Why not wait until you're 18?
I agree with the earlier poster.
Your 'crush' could pay very dearly for any sexual encounter with you.
Many persons flirt and take chances with others whom they have no real intention of having sex or relationships with.
This teacher was probably just provoking you, maybe seeing how far he could go with you, or just teasing you about your probably painfully obvious crush on him.
It's okay to tell him how you feel in a non-sexual way and situation AFTER you've left high school.
He will probably be touched and flattered, but don't expect anything more than that - for both your sakes.
A "Crush." Well that and the 5th grade grammer kinda says it all. Leave the guy alone and stick with who you called, "boyfriend." In about 5-7 yrs when you turn 18 go back and visit one day and see where it goes if you want. Until then, STAY AWAY.