Manga by author Hashimoto Aoi

From Exiled Rebels Scans:Thirty-two year old Suwa Misumi is a Master of Sake and has just recently been fired from his job due to causing trouble from being "too friendly" since he doesn't like to refuse requests. At the lowest point in his life, he now finds a restaurant he desperately wants to work at. Only problem is that his latest drunken one night stand is the owner!!

In the Between the Sheets series:V.1 - Between the SheetsIchise lost in somewhere he didn't know then later found night bar that has amazing bartender, Takafumi. Ichise fall in love with Takafumi at first sight but Takafumi has his own rule that he will never go out with his customer. One day, Ichise tried to ask Takafumi out again and suddenly Takafumi says yes'!?V.2 - Blue Moon, Blue