Gohoubi wa Yoru ni Choudai

"How is it? Sweet, right?"

One day on her shift as library assistant, Hinano finds ultra-popular ladies' man, Haruna Iori, sleeping amongst the stacks. Not only does he tease Hinano relentlessly, he also somehow ends up stealing her first kiss! Hinano decides to pretend it never happened and goes home -- only to find Haruna at her house, too? That's when Hinano's mother breaks the news to her: she'll be living with Haruna for the next six months! Hinano's heart is sure to beat out of her chest sharing a space with the free-spirited Haruna, whose advances only grow sweeter and sweeter!

(Source: MangaPlaza)