Seito Kaichou de Amaenbou na Onee-chan wa Suki Desu ka?

Mio is the student council president who happens to be a neighbor and childhood friend of Yuuhi so he is not spared from the jealousy of his classmates and other male students. They could have been more jealous if they just know how they are back at home. Mio and Yuuhi are actually a pair of lovers and their formal treatment towards each other is nothing more than a cover-up to conceal real intimacy.