The BL is set in the omegaverse and it’s about an uke that has been following the seme since I think high school or earlier I don’t remember. The uke is in his I believe first year of college and the seme is in his last I think. The seme who is an alpha hates omegas because he's sensitive to the smell of pheromones. The uke has a friend who’s parents own this vip place for alpha’s to spend their rut. The uke decides that since he won’t be able to follow him after college/university he would have a one night stand with him and asks the friend to set him up as if the seme had requested him. The uke then proceeded to cross-dress and sleep with the seme the seme realized he was a guy but didn’t care at the point. After several days I believe the uke leaves the vip place but before leaving leaves a score on a sticky note that makes the seme try to find him and also because the uke’s pheromones didn’t bother him.

Is it Recessive Omega K's Secret
If so you can also read the first 2 chapters officially translated here
https://toomics.com/en/webtoon/episode/toon/5617