https://www.pixiv.net/en/users/1742503

the honor student with a strong sense of justice and her kind-hearted yankee friend become the next playthings..

full story is available in Pixiv description
https://www.pixiv.net/user/1742503/series/20182

no.01: main story (with chapter break)
no.251: bonus artworks from https://www.pixiv.net/en/artworks/63420180
no.254: bonus artworks from https://www.pixiv.net/en/artworks/64491731
no.260: bonus artworks from https://www.pixiv.net/en/artworks/70041704