I saw a movie in the late 80s with my brother on Cinemax After Dark about a blonde who is sent away to an all girls etiquette/reform school when her parents learn she is interested in sex. The institute she lands in is very high-end and was once a castle or chateaux somewhere in Europe. She is bullied by some of the girls and I think befriends her dorm mate, maybe a brunette. Anyway, my brother & I quote a line from that movie all the time. There's one scene where the girls are learning table manners and proper silverware names. One of the girls is asked to name a particular fork and gets it wrong. The instructor (a male with a thin mustache & a French accent) slaps her on the wrist with a paddle and says, "That's not a dinner fork! It's a salad fork, you silly cow!" In another scene, the naughtiest girl (blonde) gets it on with one of the instructors after class and is caught by the school cameras. The dean or head of the school is a spineless & shady male character. I think the main character (girl sent by parents) eventually loses her virginity to an instructor or hired hand, perhaps in the wine cellar. I recall the girls sleeping in white panties with skimpy white baby-doll tops or poet shirts. The dean is blackmailed and eventually busted for filming the girls without their knowledge. If anyone can remember this late 80s (possibly early 90s) movie, please pass it on. Thanks!

It kind of sounds like Strike! (1998) in some parts you described but it might not be the movie you're looking for.