In the Realm of the Senses (1976)

Original title: Ai no Corrida. This controversially explicit Japanese film is based on a true story set in pre-war Japan. A man and one of his servants begin a torrid affair, and their desire becomes a sexual obsession so strong that to intensify their ardor, they forsake all, even life itself.

This includes a scene of two women sitting on the floor and juggling small stones during a singing game that is shown for almost 30 seconds.