Cherry Blossom's manga / #rivals(2)

Top students Kawase and Kurihara have been locked in an intense rivalry since the start of high school, unbeknownst to Kawase. No matter how hard Kurihara studies, he can’t seem to take the top spot. Kawase, taken aback by Kurihara’s hostile and self-damaging behavior, becomes determined to help him in any way he can.

Rivals since high school now salesmen in the same company, constantly bickering and betting on things to see who wins. This time the winner is whoever makes the other fall for them first, but uke doesn’t know seme has liked him since high school