Hentai niku nure vibe(2000)

Ayaka harbored a persistent fantasy that a penis was growing from her crotch and was conducting her own research on the matter. One day, a man named Kawamoto approached her on the street, asking if she would work as a nude model; in exchange, she demanded that he allow her to pursue her research on the penis. However, because Ayaka showed no interest in his proposal, Kawamoto tried to have another model, Donna, convince her of the job's perks. Instead, Ayaka hit it off with Donna—who herself harbored a fantasy that teeth were growing inside her vagina—and...