Imp's Grand Plan to Take Over the Country

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!

Matsushita Ukyou is typical mama's boy. One day, he receives a call from his grandmother, Chichiizumi Touka, asking him and his mother to visit the Chichiizumi Shrine, where she holds the title of Milk Shrine Priestess. However, it turns out to be more than a simple call when the priestess announces that she will be retiring! Ukyou must perform the chichi miko training with three beautiful women, his mother, aunt, and cousin, and determine which is fit to succeed as Milk Shrine Priestess!

There is a program described as “Male and Female Practical Education”, it all started with a single classroom and eventually spread to others. This summer break Arita Atsushi was enrolled in this program. He's afraid he won't talk to any of his classmates because he gets nervous talking to others, especially girls. He doesn't know anything about this camp other than it's being held on a remote island, and he's really hoping the experience changes him for the better.

Aoi's erotic summer vacation begins when his mother tells him that she is going to do "mother-swapping" with her friends!

My childhood friend was stolen away from me by a perverted bastard...
But that was only the beginning of her fall. By the time I realized, it was all too late...
 
Oblivious to the truth, the protagonist blindly sits on
his 'childhood friend' pedestal basking in self-conceit.

To fill a gap in her heart, she seeks the warmth of others
...and is abused and exploited by strangers in return.

Yet nonetheless, she is happy to know that someone 'needs' her...