I note that this film is supposedly based on a novel... this seems to be a common theme for a lot of the softcore movies of this era. Note Emmanuelle, Lady Chatterley's Lover, Joy: Chapter 2, Justine, etc.
Anyways- I will admit to having been a softcore porn fan in my raging-hormones youth. I taped all of the "late-nite" stuff on Showtime and Cinemax, and watched quite a bit, and became quite a critic. Much of it I couldn't stand... but this was one of the exceptions.
Secrets of the Satin Blues follows the time-worn and cliched plot device of following an inanimate object around, and watching the effect it had on various people. And, like many movies using this plot-device, it all rotated about sex.
The movie starts out with a lady buying some satin blue underwear from a shop; she wears it and begins having softcore sex. The underwear gets misplaced, the maid tries them on... the maid begins having sex. Etc. I'm doubtful that the book this is based on is a classic... but the movie is pretty fun, in a sleazy sort of way. None of the actresses are very attractive, nor do the guys seem to belong in a softcore film. (Indeed, the director apparently thought so, as 2/3 of the sex is lesbian- the first lady sleeps with her best friend, then her maid- her daughter catches her with the maid, prompting a flashback of the maid and daughter having sex. This prompts another round of lady/maid sex...)
What did I like about the film? Well... considering the men are pretty gross, it's a plus that they were so minimal to the plot/sex. This was a big problem with 70s/80s Euro-porn. The women may not be that great either, but they don't look like they are made from grease and hair, and this makes the frequent sex scenes tolerable. The storyline itself is a bust, although the fact that the US editors dubbed in a voice *for the underwear* made it come across as a really whacked-out comedy. This is what makes the film fun- the cheese factor. It isn't really erotic, it definitely isn't dramatic or emotional; what it does have is a hell of a lot of personality, a type being erased by the intrusion of slick made-for-cable American "erotica" productions like Red Shoe Diaries or Beverly Hills Bordello- productions with no personality at all.