Usotsuki Omega ha Sakaraenai

An omega who was pretending to be a beta is suddenly the mate of a top tier alpha!?
It happened one night on their way home from a company drinking party. When Mr. Hashida takes care of the drunken Mr. Hayashi, just a small amount of Mr. Hashida's omega pheromones is enough to drive Mr. Hayashi into a frenzy. Despite his resistance, Mr. Hayashi not only has his body taken, but Mr. Hayashi bites his neck indicating that they've become mates. However, it seems Mr. Hayashi remembers nothing from that night... Mr. Hashida considers himself lucky and continues to pretend to be a beta. He decides to hide that he's his mate forever, but Mr. Hayashi (an alpha) keeps desiring his body!
(Source: Renta!)
Note: Chapter count includes one extra.