Suki ni Naru Made Matte(2007)

Whenever it was break time, Hikami-kun sat at my desk and talked with his friends. I was concerned about it, but since he is a hot guy I couldn’t say anything about it. On that fateful day, I dropped Hikami-kun’s cell in the fish tank, and now I have to be his slave?! (Source: Manga Abyss)

Also includes:

Uso to Koi no Hajimari - Tomoko's childhood friend "Ken-chan" comes to Tokyo and wants her to show him around. Tomoko can't be bothered, so she sends Akane to pretend to be her instead...

1/3 no Kareshi - When Rei visits the junior high section of the school, a mysterious guy takes an embarrassing picture of her and refuses to delete it unless she meets him again later...

Deatta Toki ni Boku wa Mouinai - Yoshii Shougo never talked to Ashizawa Yuu before he was in a fatal auto accident, but now his spirit can't move on without her help...