Natsume didn't want to tell you he was a vampire. He feared you'd leave him once he'll tell you that. He treasured you too much for you to leave him. One night, he came back home, and saw you sleeping with your laptop on, and countless papers on the table. Natsume knew about your projects, and tried to help, but you denied. To wake you up, he decided to bite your cheek. Natsume didn't want to admit it, but he was dying to know how your neck tasted. Keeping himself under control was difficult.