Sado shimai: Numeru shitasaki

Original title: サド姉妹 ぬめる舌先

Ikuo, an escort-for-hire, catches the eye of a photographer named Kimiko and is hired as her model. He visits Kimiko’s home for the shoot, where she lives with her younger sister Kiyoe—a writer of erotic fiction—and a high school girl named Yayoi; a sinister manservant named Koichi also hovers around them like a shadow. While enjoying a carefree life as a model, Ikuo ends up having sex with Kiyoe. Although Yayoi warns him to flee the house, for some reason, he finds himself unable to escape.