Kiss My Blood

Tetsu is just an average teacher looking out for his childhood best friend, Shima, who is actually a vampire. To an outsider, they are merely teacher and student. Since Shima is a vampire, he has to drink blood to appease his hunger. Usually, small animals such as cats and pigeons suffice, but Shima's feelings of love and jealousy make him crave for Tetsu's blood. The latter readily gives his blood and makes Shima promise to drink blood only from him. Things get more complicated as Shima's vampire instincts get stronger.

(Source: Futekiya)