Lovephobia

From the Japanese Back Cover:

Now, open the door to the corruption and welcome a story of sensuality...
The life of Ako, a quiet 16-year-old schoolgirl, is suddenly covered in blood when a fair compelxion vampire, Koh, appears and bites her. While her blood is sucked she feel an undescriptable pleasure in all her body. "Come and hunt with me" were Koh's words when he finish to bites Ako. A vampire story of sensuality from the hand of Natsume Kokoro-sensei is finally here!

From Digital Manga Publishing:

Ako stumbles into her parents'' murder scene while the killer still lingers over them - a vampire named KOH! He turns his attack on her and viciously drains her life, but even as she dies, her terror and revulsion turn to... pleasure? Now, Ako has joined the ranks of the undead, feasting upon humans at her master''s command, but what will become of her only living brother? The poor boy still awaits his sister''s return, never knowing that another vampire hunts him from the shadows.