Onee-chan no Sourou Kaizen Lesson ~Dashisugi ni Gochuui Yo♪~

This is a meeting room with the school counselor. Shuua hears a rumor that a male counselor is coming to the school and decides to talk to him about his current problems.

However, who arrives is actually his sister Mikako!

"Huh!? What are you doing here, sis!?"

At first he was hesitant to reveal his concerns, but Mikako's earnest response made Shuuta comfortable enough to share it with her.

The problem was that he has premature ejaculation during his first time with a girl. It was simply a handjob. His partner laughed at him for cumming so quickly. He is also a premature ejaculator when masturbating.

When Mikako saw that her brother's future was in jeopardy, she took the plunge. She took off her clothes down and thus began their lesson in overcoming premature ejaculation.

[From official site]