The Siesta Mates

Socially, omegas are lowly regarded and the world in this story is just like modern Japan. To correct this social inequality, the "omega employment act" was passed and it requires companies to actively hire omegas. The main character, Arata, is an omega and he's one of the many hired by a major company thanks to this act. His company is a famous one where it's hard even for alphas and betas to be hired, but the role he's given there is a special type of "slave" that has to take care of certain needs of his alpha and beta co-workers... Due to his stress, he doesn't have regular heat cycles anymore. Full of mental and physical exhaustion, one day Arata stumbles upon a cat cafe on his way to work and decides to use it as a napping spot. There, Arata meets the cafe owner, Touya. But, when the two come close together, Arata goes into heat even though he's not supposed to...

(Source: Renta!)