Li'l Miss Vampire Can't Suck Right - Chanto Suenai Kyuuketsuki-chan

Synopsis

With her cool, mysterious aura, transfer student Ishikawa Luna is already the most popular girl in class. Ohtori, on the other hand, is so average he's practically a background character. The thought of ever speaking with Luna never even crossed his mind—until he accidentally discovers her secret: She’s a vampire…who's absolutely terrible at sucking blood!