Mother Knows Breast - Season 1

Takeshi's mother Shino and sister Shinobu are not biologically related to him. The family appears outwardly peaceful, though Shinobu is attached to Takeshi while seeming to reject her mother. A secret exists within the household. At night, Takeshi is brought into Shino's room, where he is compelled into sexual acts against his will. He complies because he fears Shinobu would look down on him if she learned of the relationship.