Looking for a BL

my Sister was talking about this Yaoi manga but she didn’t want to tell me the name, but she told me the overall plot. It goes like this.

A psychopath summons a demon just for the fun of it and the demon says smth along the lines of “your soul in exchange for a wish” and basically the guy says “I wanna eat you” and idk what happens but it’s bloody and they end up having sex..? Then the demon murders the guy and carries his head around until he can find a new host for the guys body.

She told me the name just consisted of 4 random letters and that the manga never shows up on the home page — basically it’s very underrated. It has around only 5 chapters.

Please help me find this manga!! Thank you so much!! :>