Tsuki To Himawari summary:

Asahi-kun is a carefree junior-high student, never attaching to girls even though he enjoys going with them. But when the school's number 1 honor student Mitsuki "cyborg" Konno asked him to a 1-month date, in exchange for the front row ticket to his favorite singer's concert, he was forced to accept. He only has to show her what it feels like to date, right? He is ready for that...however, what he's not prepared for was his heart's reaction... -- Baka-Updates