Oyako Onanii: Inran Daikyôen (1999)

Tatsuko, a widow, has a voracious appetite for men. When she and her daughter, Chiaki, simultaneously reach orgasm while masturbating, their souls end up swapping bodies. Shocked as they stare at one another, they decide to go about their lives in each other's bodies for the time being. Feeling as though she has regained her youth, Tatsuko indulges in sexual escapades with men using her daughter's body. Meanwhile, Chiaki—who is still a virgin—experiences intimacy with a man for the first time using Tatsuko's body...