Stop it! Onee-Chan! I’m gonna cum! (やめて！ お姉ちゃん！！ 白いオシッコがでちゃう！！)

The main character, Yu, had Miwa, an older sister.
However, the excessive contact with Miwa of the super bracon was revealed,
and Miwa went to a boarding school to correct the bracon and was separated.

However, Miwa graduates from school and returns home.
Miu, who resumed, grew beautifully enough to be seen, but the
attitude was harsh and cold, different from the old days.
Yu is shy if she is not a kind sister.