Beppin Mama ~Love Love Boshi Yuugi~

Akira, studying for his entrance exams next year, spends his spring break alone with his beloved mother, Chizuru.
Chizuru is the envy of all his friends, and his favorite beautiful mama.
She teaches him kindly and slowly all he needs to know for his exams.
But it's not studying Akira needs to worry about, it's his Aunt Kanae, who's come to live with them!
His real mother, a widow and a former teacher who spoils her son,
and his Aunt Kanae, an active spartan teacher who laughs at Akira's weaknesses.
Akira starts to learn about the sweet and harsh world of adults.
His full-figured passionate mother and aunt become his tutor in the arts of ejaculation!
He becomes a slave to the wills of these hot-tempered women, full of sexual desire...

[From DLsite English]