Flower and Snake: Ultimate Rope Discipline (1987)

A man's gambling debts pile higher and higher and he is desperate enough to have to do something. Well, he can sell off the two women closest to himself of course. The yakuza are buyers of course. The sold mother and daughter are now sexual slaves and while the mother attempts to bargain for her daughter's freedom nothing gives. Escape is also futile.. or rather worse than remaining put.