Juku Chichi ~Mama no Karada wa Boku Sen'you

Yoshihiko, a student who is studying at home for the entrance exams, has feelings for his mother, Naomi, that go beyond parent and child since he was a child.
Yoshihiko has come of age without a girlfriend and is now in his third year of studying at home, he's stressed about his entrance exams and can't concentrate on his studies because he can't resist the allure of his mother, Naomi's ripe body.
Every day, he secretly pleasures himself by looking at his mother's body, but his actions gradually escalate.
Eventually, Yoshihiko could no longer control his desire, and he ended up making a move on his biological mother...

[From Getchu]