Senpai, Danjite Koidewa! Brush up

CG designer Kaneda has gotten into a romantic relationship with his supervisor, Yanase, whom Kaneda idolizes like a god. Kaneda tries to do his best at work, but he’s so overjoyed to be next to Yanase that he finds himself getting nowhere! Unable to focus on his job—especially when Yanase’s excessive physical intimacy makes him melt on the spot—Kaneda tells himself things can’t go on like this...

(Source: Yen Press)
Note: Includes 1 extra chapter.