"A Teacher" aims big but often misses. The ultimate message of the series is that a groomed student, even a "willing" 17/18 year old boy, is always going to suffer, but the point is not handled deftly; that conclusion feels unearned with lazy characterizations of the people the boy Eric interacts with, or even the 2Dishness of the characters Claire has in her life. And the earlier sex scenes between the characters are shot quite provocatively, which left a bad taste in my mouth given the subject matter. I think the show had a point to make, but ultimately failed to achieve its goal.
I will add that the actors do a fantastic job, and they were the part I found most tolerable.