Source https://www.pixiv.net/en/artworks/106315572

Yuka is the little sister of Airi, the ace of the ninja girl school. With her preliminary formation done, she is almost ready to join the ranks of the elite class... but before that, she must proves herself to the master of the girls during a lewd, all-out bout of erotic ninja sex battle all night long ! Despite her inexperience, this pure and charming young ninja girl must now find withind herself the way of a true, debauched ninja slut and overcome the many big, hard cocks of her teachers...