Main is an incubus uni student an he has to sleep with a quality human and take his soul (basically kill him) to graduate and become a full proper incubus. However, the human that was chosen for him has erectile dysfunction and can't perform. So main does a little research and finds several major issues that could be causing the ED and goes to work to get his human sex project healthy again by fixing his diet, sleep schedule, and work schedule.
OMG little demon incubus is so sweet kind and caring, and he's so adorable too. Even though it's so he can have sex he's still so worried about his human project. The fact that the human project just accepts this is hilarious, he's like " yea sure I'll let this demon take care of me for sex" lol
Inma-kun wa Oshigoto Dekinai