Katsuai Monster Manga Summary
From Fantasyshrine:
Kabutani is a “man-eater” who lives off human energy. One day, he becomes “in-heat” for his classmate, Kiriyama. Though he didn’t believe when his kindred said, “…Nothing compares to the taste of the ‘human’ you love!”, he couldn’t resist a “taste” of Kiriyama… And once he had, he became addicted to that tantalizing taste only Kiriyama can provide. What would a hungry and ruthless Kabutani do to curb his craving…!?