From Evil Flowers:
A short oneshot about the Demon of Love; the Incubus who, in order to become a Full Demon, needs to feast on the essence of 10,000 women. However, the last woman he chooses is actually a boy?! So, the Incubus decides to live with the boy, until he has completed his quest to become a Full Demon. It’s not shounen-ai, just a comedy.
