An Doeneun Sai

Alpha Yeong-Han and Beta Min-Jae are set to become a family through their parents’ romance. Yeong-Han, who has been acting as an older brother to the trouble-making Min-Jae, goes out to buy cold medicine and is suddenly confronted with Min-Jae’s sudden Omega manifestation. Losing control, Min-Jae throws himself at Yeong-Han, an Alpha. Yeong-Han tries to run away, but he can’t escape Min-Jae’s pheromones… and the two end up getting into trouble.

(Source: Bomtoon, translated)