My suggested MPAA rating: R for sexual content and themes, strong language and smoking.
VIOLENCE: 2/5 - Sheba's behavior gets pretty tense and infuriated, but that's about the highest peak of all the violence we see, surprisingly.
SEX: 5/5 - A teacher willingly has sex with her student, and that provides the film's whole plot. I'll leave it at that.
LANGUAGE: 4/5 - One or two uses of "c--t", at least 15 uses of "f--k", plus lots of anatomical references.
DRINKING, DRUGS & SMOKING: 2.5/5 - In one or two scenes, a student asks his teacher if she minds him smoking a cigarette with her.