Shiro To Tsubaki summary:

Tsubaki, who is half-incubus and half-human, cannot live without consuming human energy. He supplements his energy by getting it from Hakuomi, an exorcist who's also his childhood friend and classmate. These days, Tsubaki's incubus side seems to be getting stronger. He barely lasts two days after being with Hakuomi. Embarrassed, Tsubaki tries to hide the truth, but Hakuomi sees through him. Although Tsubaki doesn't want to burden Hakuomi, Hakuomi wants him to rely on him even more. But, Hakuomi has a secret he can't tell Tsubaki...!+