I have been trying to find a manga I read a while back, many years ago. It is in Omegaverse story where the main characters are from an orphanage and the Alpha end up biting an omega during is first rut, but his friend decide to pretend he was the omega bitten, so he started to use pheromones perfume to mimic heat and had a tattoo of the bite mark. They started to date, lived together, etc .The alpha does end up knowing the truth and the friend explain everything he did to pass as an omega. I don’t remember it being a long serie.
Hopefully someone out there knows what it is! Thank you!