Mama Natsu ~Boku-tachi no Mama Koukan~

The protagonist, Makoto Sakurai, is a high school student.

One day, his new neighbour, Atsushi Uchiyama, tells him an shocking secret about his family: he has a secret sexual relationship with his own mother.

For him, it's completely normal. But ever since, Makoto's way of looking at his mother, and at his friends, has changed.

Then, one day, Makoto's father has to leave for an extended business trip, leaving Makoto alone with his mother. Makoto feels something vaguely unsettling, and his concerns turn out to be a reality.

That day, when he comes back from school, his mother is waiting for him completely naked, ready to start an incestuous relationship with her son. And it looks like his friends are in a similar situation!

♡ A lewd, lustful nun older sister & a mean, vulgar bunny girl older sister ♡
You’re a pure, petite boy captured by naughty, busty older sisters, forced to do nothing but be made to climax by the older sisters you love so much…!

Summer vacation is finally here! Our story follows Natsu, a timid, effeminate young man who embarks on a family trip to the countryside to visit his aunt Misaki. But just as everyone's getting settled in, a mix-up at his father's workplace forces Natsu's parents to hop right back in the car and drive home, leaving him to spend the remainder of his summer break out in the sticks. Misaki is more than happy to take him in, of course, and so begins a peaceful, relaxing few weeks where absolutely nothing out of the ordinary threatens to disturb his tranquil everyday routine... Bwahahaha, as if!

It isn't long before a self-proclaimed magical girl named Chitose worms her way into Natsu's life, but her boisterous intrusion is the least of his problems. An eccentric candy seller, an insecure wanna-be teacher, a pink-haired loudmouth... Not to mention, his aunt's strange behavior around the topic of the outdoors. Surrounded by misfits, it soon becomes apparent that Natsu's real summer homework is to learn more about the women around him and help them with their problems. And yet, with only 30 days until his parents pick him up, is this one assignment he's fated to flunk, or will he pass with flying colors?

The main character, Makoto Kougami, has just transferred to a new school. He has a crush on his beautiful math teacher, Shiori Toono.

She is a serious and inflexible girl who is not well received by the male students. However, Makoto is crazy about her.

One day, he sees her taking care of a cat. The two quickly become closer through their common topic of conversation about the cat she keeps at home.

Can Makoto be able to break down her firm guard?