Mayohiga no Onee-san THE ANIMATION

Isamu suddenly stopped by Mayoiga's cafe. It turns out that he thought from the outside look different, when he entered he was greeted by Natsuki. Get the sex, love, and heaven service from the cafe. Natsuki also tells him, if he gets good grades during the exam, they will celebrate. When the day comes, another Onee-san Akiba comes along who wants to sex with him. (Source: Nekopoi and Has Been Translated)