Koisuru Tetsumenpi summary:

Kitagawa Ryouno is the company's most popular hottie, and the ace of the Sales Department. But he has a secret he can't tell anyone. He's a coward, whose face turns red from any unexpected turn of events.
Therefore, from the day he noticed that he would calm down in front of his strict and awkward senior Natsume, the hope of Development Department, he became attached to him.
On the other hand, Natsume has his secret, too. He's gay and has his eyes set on Kitagawa, ever since he joined the company... 4 years ago.
Thus begins the impossible office love affair of a Sensitive Salaryman (Straight) x a Workaholic Employee (Gay)!