Phantom Dog -birth-

What exactly am I being shown here──
Sakaki, who has despaired of life, knowing neither love nor being needed by anyone, arrives at a certain park.
Then, from the nearby bushes, he hears a dog-like whining sound...
Curious, he peeks in and sees a man wearing a dog mask, "Jin," being penetrated by a suited man, "Ukyo."
Unable to look away from Jin's eyes, which greedily crave life in stark contrast to Sakaki's own desire to die, Sakaki ends up getting involved in the two men's act.
As a result of that night, Sakaki is ordered by Ukyo to take care of Jin's daily needs, but as he spends more time with Jin, his feelings begin to change──!?

Original JP: Chillchill | cmoa