Haraguro Kareshi wa Dekiai wo Kojiraseru

"A wicked boyfriend gets love all twisted up." High school girl, Nonoka and her childhood friend, heir to a large corporation, Kyoichi. Nonoka was used to being treated like a little sister by Kyoichi, her sweet childhood friend. However, this same Kyoichi is infatuated with Nonoka to the point that he'll do anything --- devise ways to keep men away from Nonoka, enact elaborate plans to sleep with Nonoka and even blur the lines of their friendship with the occasional hickie or bite to mark Nonoka as his. Is this dose of blind infatuation too much or just what the doctor prescribed? (Source: MangaPlaza)