The trigger is your everything

Akiha, a trimmer who hates people but is well-liked by everyone because of his calm demeanor, is put in charge of training a newcomer, Hizuki, who is not very sociable. Hizuki is strangely getting attached by animals, but is hopeless at customer service, and Akiha has a hard time dealing with him. One day, when Hizuki gets drunk at a welcome party and Akiha takes care of him at home, he hugs him and confesses to him. He dismisses it as the ramblings of a drunk, but the next day, Hizuki continues to make passionate moves on him...?

(Source: Kaiohsha, translated)

Note: Includes one extra chapter.