I remember seeing "Flower and Snakes,"
based on Dan Oniroku BDSM literature from 60's (or 70s).
It was quite something, with the popular japanese actress Sugimoto Aya totally naked, penetrated by dildos, forced to have lesbian sex, etc... I really liked the ways this lesbian sex was portrayed - while the sex itself was occured by force, its sexual expressions were shown as homoeroticism or sort of sisterhood love.
I went to see that with an established professor whose specialities included films and she was quite impressed. I would really love to see its sequel film, part 2 (I know it is already available at the rental video store in Japan).