Soitogete, Ryuujin-san  

The sudden emergence of "Ryuugaeri" has transformed the world by turning normal individuals into dragons. This new species, referred to as "were-dragons," have been accepted into modern society despite their unique way of life. When a dragon falls from the sky in front of high school student Murasaki Kurogane, he takes it upon himself to feed Tsukumo, who reveals that he has no place to go. As a gesture of kindness, Murasaki also offers his home to the were-dragon. However, as night falls, Tsukumos intense fear of loneliness intensifies and transforms into a need for human warmth. While half-conscious, his desire turns sexual, and unsuspecting Murasaki becomes the warmest thing he can find.