Hibari-kun no Ω

Reo, a high schooler respected by his peers for his fighting prowess and un-Omega-like attitude. He'd never gone into heat once, and had never been attracted to either Alphas or Omegas.

One day, an Alpha college student who heard rumors about him catches Reo and drags him home. Reo is hit by an Alpha's intense pheromones, a heat rising from deep within his gut like nothing he's ever felt before, triggering his heat. But that scent is coming from another boy in the house... Ryusei?

(Source: cmoa, translated)