Tedama ni Toritai Kurokiya-san is a Manga/Manhwa/Manhua in (English/Raw) language, Comedy series, english chapters have been translated and you can read them here. You are reading chapters on www.mgeko.cc fastest updating comic site. The Summary is

Kurokiya Ruu is on the verge of repeating a year so her childhood friend Tadashi Tadao (whose name literally means straightforward man) steps up to teach her. However, they end up not getting any studying done as she uses this situation to try and seduce him at every turn.