A 39-year-old marketing department manager. He's kind, competent, and well-liked by his subordinates. He hasn't dated in over 10 years, and the only person he talks to is a stuffed sparrow. With only three months till his 40th birthday, he makes a list of "10 things I want to do before I turn 40," but...

(Source: BE BOY, translated)

Suzume Tojou is just three months away from turning forty and realizes there’s so much he hasn’t done with his life! So, he makes a plan: create a private list of things he’s always wanted to do and check them off before turning the big four-oh. It’s a rather simple list, filled with goals that should be easy to accomplish, like a takoyaki party, enjoying a parfait out in a café, and spending his birthday with a lover. Except, that last one comes with a major problem—Tojou hasn’t had a lover in ten years! But when Keishi Tanaka, Tojou’s handsome junior at the company, discovers the secret list, he’s determined to help Tojou check off every single item—starting with the “lover” part!
 
(Source: Seven Seas Entertainment)
 
Note: Contains two bonus chapters.

My first morning and my first Christmas after turning 40. 
A special one-shot that takes place the day after the final chapter.
 
(Source: Libre, translated)