Sadism.

Miho and Taka have finally gotten used to living together. However, Miho has been coming home late recently and her replies to messages are sparse, making Taka feel a distance between them. He accidentally sees a text from a guy inviting her out, and when she comes home late smelling of cigarettes without contacting him, his jealousy explodes. He forcefully pushes Miho down, covers her body in hickeys as 'punishment'...!