なつえっち ～めいといなかのなつやすみ～

To visit a gravesite with her parents, Mei goes to her uncle who lives in the countryside.
After a hearty banquet, she becomes infatuated with her sleeping uncle's nether region. One thing leads to the other, and in the end she loses her virginity to him.

With having the basics taught, Mei learns of the pleasures of sexuality so she and the uncle - her diligent teacher - will spend the remainder of the summer holidays together in the countryside.

Mei actually got a boyfriend, an exchange student from abroad, however, they never have as much as kissed before.