Tenohira ni Suisei

Mashiro Haruno hopes to become a designer, so she gets an internship at a famous company. The night before her very first day though, she ends up getting really drunk due to nerves and winds up having a one-night stand with a pretty attractive guy. However, it turns out that the guy is actually her manager at the company!! Even though she has no memories of their one-night stand, she's pretty sure that he was a nice guy, but now that she's working under him, he's just a big bully...!?

(Source: Clairparfait)