完璧お姉さま御子神沙耶の無人島孕ませ修行～ふふ、元気のいい精子だ…早く私に妻の証を宿してくれ～

Protagonist Yosuke Ikeda was reminded of his own shortcomings in the daily presence of cool-headed, talented, universally popular lady Saya Mikogami.
She saw him being humiliated for his lewd tendencies and decided to fix him up by taking a private holiday to an uninhabited island.
At the same time as they trained Yosuke and Saya became lovers, as she showed him the ways of sexual discipline... a splendid baby-making life with the cool, perfect older girl!

[From DLSite English]