Ichizu Osananajimi wa Gamandekinai: Kyuuketsu ni Youyín Sayou ga Aru Nante Kiitenai!

Yuzuki Arisugawa is the daughter of a company president and a member of the school's public morals committee. The sheltered young lady is so naive about love that she overreacts to a couple just holding hands. But at least she gets along with her childhood friend Kagari. One day, Yuzuki suddenly turns into a vampire and sucks blood from Kagari! Moreover, when she sucks blood, her victim goes into heat, and Kagari, who has always had a crush on Yuzuki, can't hold back anymore...! (Source: Manga Park, translated)