Incest at a relative's house

Since he was a child, Mitsuru grew up under the care of his mother, Shoko. As Mitsuru grows older, Mitsuru's love for him becomes more and more distorted, and Shoko has no choice but to accept it. One day, a memorial service is to be held at the house of her sister-in-law, so Shoko and Mitsuru leave their busy husbands at home and go to their relatives' house for the night. That night, Mitsuru, who is happy to be alone with his mother, indulges Shoko, ignoring the fact that she is living with a relative. Even though Shoko knows that she shouldn't, she steals away from her relatives and takes Mitsuru's hard cock into her mouth...