Sensei Datte Kareshi Desu

This spring, Io Yumabuki will start her second year of high school. At the opening ceremony, Wataru Naruchika, a childhood friend of hers, shows up as the new art teacher. Io and Wataru were next door neighbors and have been close family friends since childhood. But... they actually became a couple 3 months ago! Friends, lovers... and teacher! It's a heart-pounding relationship with "Naruchika-san"! A fearless adolescent love comedy!

(Source: Comic Days, translated)