It's a Japanese pink film called Teacher Clinic Temptation, about which the imdb knows nothing. Even I was assuming this would be garbage.
Firstly, I'll run through all the information on this film that I could find in English. Its Japanese title translates literally as "Female Teacher, Infirmary Seduction" and it stars someone called Miki Aoyama, who doesn't appear to have an acting career. Well, that was quick.
Nevertheless, it's surprisingly good. Not by real standards, mind you. Show it to a normal person and they'd probably say it had sub-standard acting and looked as if it was made for tuppence. It probably was. However I don't think they'd necessarily realise that they were watching pornography and personally I quite enjoyed it as a regular film. It has sex scenes, yes, but they're not explicit and you're certainly never left wondering or not the actors are really doing it. Yet again I've been surprised in a good way by a Japanese pink film... and this isn't even one of the famous ones, although I presume it must be above average for me to have stumbled across it in the first place. There's so much Japanese porn that I assume there's a Darwinian "survival of the least unwatchable" in what gets torrented.
There are four main characters - the teacher (Miki Aoyama), the student, the mentally unstable ex-boyfriend and the schoolgirl slut (Risa Kawamura). The first thing you need to know is that despite the title, this isn't a film about temptation. On the contrary, both Aoyama and Kawamura have psychological issues about sex and their fathers. For one of them, those used to be the same thing. That's quite a speech she gives when we learn about that, made all the more shocking by its understatement.
Anyway, Miki Aoyama spends the whole film not wanting to have sex. When her ex-boyfriend turns up, this causes fireworks. Kawamura, on the other hand, has moved out of home and is supporting herself with enjo kosai, which I hope you're lucky enough not to know what that means.
As for the men, I think I've said all you need to know about the Ex-Boyfriend. The Student though is quite interesting. I liked him. He keeps getting into fights and getting beaten up, which means a trip to the sick bay for bandaging by Aoyama. What's good about him is that he's not a stereotype. He's capable of being lecherous, but he's also honourable and doesn't want to have sex for the wrong reasons. He gets into fights... and loses. He's cocky, but sensitive. He develops strong feelings and in the end becomes a romantic figure, but is also capable of reacting like any teenager who'll be casual towards the people around him and walk out of the door without giving them a second thought. In other words, he's as likeable and complex as he needed to be to live up to a storyline that includes Aoyama and Kawamura.
However his character does get a few plot goofs, which a top-class actor could have perhaps turned into characterisation. Why does he hide in that cupboard in the beginning and why didn't he take those tights off his head? Why does he seem to lose all his fights, but then manage to knock down two yakuza?
Acting-wise, Aoyama is the weak link. She's downright bad in the first half of the film, although she gets stronger dramatic material to play in the second half and responds well to it. The Student is likeable. The Ex-Boyfriend is successfully what he is. However I was mildly impressed by Kawamura, who puts in a lot of emotional energy and is capable of having a strong effect. Note the scene where she's throwing out reasons why the Student might not be interested in her sexually, for instance. That could have come across as petulant or slutty, but she makes it powerful. She knows she's damaged goods. You feel her pain.
The storyline's simple, but that doesn't mean bland. Kawamura's choices lead us down a road to unexpected bad places and leads to Aoyama making a choice for which I wouldn't be brave enough. There are yakuza. There's sexual harassment at work from the headmaster.
In summary, I'd go so far as give this a mild recommendation. I wouldn't pretend that it's brilliant and you've obviously got to see past the surface of what it is, but dramatically I think it stands up better than a lot of normal movies. Even the sex scenes are more interested in how the woman's feeling than one tends to get in movies, either in porn or otherwise. It's not just straight to the man's dick. Perhaps the director was a woman? [Note: since writing that, I've rewatched the Japanese credits and proved myself wrong.] The important thing though is that this film has a proper storyline that's not just an excuse to jump to the sex scenes and instead is exploring the psychology of its female characters and giving them strong character development.
"Psychology is my boyfriend."