Otona no Koi no Hajimekata by KOUSAKA Akiho

Shinoki never expected to cross paths with his high school rival, Nagase, again—let alone end up working at the same company. As always, Nagase effortlessly steals the spotlight, much to Shinoki’s frustration. During a company drinking party, Shinoki gets completely wasted and is taken to a hotel to rest. But the night takes an unexpected turn when he wakes up next to Nagase… after a heated encounter he never saw coming?!