Koichiro Uno's Wet and Riding (1982)
Yoko is a housewife who's frustrated by her husband's lack of virility. She finds solace in erotic daydreams, the ministrations of a condom salesman and, eventually, the partner-swapping lifestyle.
Actors: Junko Asahina, Reiko Natsu, Maki Kawamura, Jun Miho, Koshiro Asami, Ryosei Tayama, Teruo Kuwazaki, Nobutaka Masutomi, Shinsho Nakamaru, Masayoshi Nogami
Country: Japan