From Fanzia:
Niwa won a prize in another design competition, and the individuality in her works always shines through. By comparison, her senior coworker Motoki's work is just way too normal. That's what everyone else in the drinking party was all pointing out. In spite of that, Niwa didn't criticize Motoki, and she was the only one who didn't. When she ordered another highball, he happened to see that she had some underarm hair. Later, the two of them (almost) bump into each other by the restroom, and she finds herself giving him a better look at the newly grown hair on her armpits. They end up hiding in one of the restrooms, she gets a hold of his dick, and then they have their fill of secret carnal pleasure.