Yumemiru Vampire

All pure-hearted Mamoru Hishida wants is to live as a decent human being. So he can't figure out why his life keeps spiraling out of control. Then one night, he happens upon a beautiful vampire who immediately recognizes him for what he truly is: an incubus-human hybrid, and on the brink of sexual starvation. The vampire strikes a bargain with Mamoru to become his familiar in exchange for a supply of sexual energy...but are familiars usually charged with attending manga conventions? Thus begins a strange romance between a virgin incubus and a sensual, manga-obsessed vampire.

(Source: Iproduction, translated)