The fourth installment in the Twisted Marriage series features big-ass wife Runa Tsuki, whose defining trait is that she's definitely having an affair. On nights when her husband is away, she meets other men. When her husband finds out and confronts her, Runa responds with unnatural behavior—actively seeking sex with him. The reason is simple: as husband and wife, she can't refuse. Complaining and glaring, Runa still gives in to her husband's advances and enjoys the sex. And in the midst of it, she silently allows creampie after creampie. The sole justification: "Because we're married, after all." This contradictory situation is what makes this work so compelling.