Le Sexe qui parle is a 1975 French adult film by Claude Mulot.

[1] In 1977, Mulot directed the sequel Le Sexe qui parle II, which starts with the "infection" passed by Eric to a prostitute.

Joëlle (Pénélope Lamour) is a beautiful executive at an advertising company who is married to Eric (Jean-Loup Philippe).

Her vagina becomes infected with a mysterious affliction, ostensibly after being seduced by an attractive blonde girl, leading her to engage in indecent sexual acts.

[1][2] These tales usually involve vaginas talking due to the effect of magic or charms, and often admitting to their unchastity.