Sukitte Iwasete? Manga Summary
From Girls' Generation Scanlations:
The cheerful and affectionate Hidekazu, and the thoughtful and genial Eiji. They were my old neighbors, the super popular twins. I, Ueto Shun, am in love with the younger twin, Eiji. We study at the same university and share an apartment, although I do not pay the rent... I live under the same roof, but... I am in trouble! I'm happy, but I find it problematic... The excitement of living with the person I love. I have to add that his older brother, Hidekazu, falls for a tsundere at first sight.