Re:birth

Habaki (police officer) and En (writer) are a pair who grew up together in the same orphanage. En struggles with abnormal pheromone secretion: sensitive not only to his partner, but to others as well. To make things worse, En developed a genetic mutation where common suppressants are no longer effective—at least, that's how it appears. A clueless Habaki continues to neglect his career prospects for En's well-being. On his first day as a transfer at a new jurisdiction, he begins to investigate an omega rape case. Meanwhile, producing excessive amounts of pheromones, En reaches out for Habaki as he enters his estrus cycle—almost as if he's an omega...

(Source: Kaiohsha, translated)