Yuichi Mitsu has opened a door that must not be exceeded.
He begins sex education for his younger sister, Baika.
Baika, who has learned the pleasures, seeks more pleasures and launches a “cute begging” attack on Yuichi.
Yuichi, an older brother whose self-control has completely collapsed against his too cute little sister.
With that skill, she trains her younger sister, Baika, under the name of sex education.
One day Yuichi hands a kitten cosplay costume to Baika.
Yuichi can’t stop Baika, who is not only cute but also sexy.
Her own cock is likened to a mouse, and she is chased by Baika, who looks like a cat.
The destination of the escalating stupid brothers and sisters is …