Mother-in-law, much better than my wife ... Fumiko Otowa

This film features a mother-in-law, Fumiko Otowa, who finds herself in a situation where she is preferred over her daughter. She gets fucked by her son-in-law, who has a strong desire for her. The central kink is the taboo relationship between a mother-in-law and her son-in-law, with the husband choosing her over his own wife.