Hanbun Ageru

Kurokawa is an ordinary high school student living in Hiroshima. He's uncomfortable with his always smiling classmate, Shiraki. One day on his way home, Kurokawa suddenly bumps into Shiraki wearing a blood-stained shirt. Kurokawa quickly took his hand and ran away from the scene, only to find out that Shiraki has been selling his body for a living. He injured a client and escaped.
After hearing that Shiraki never wanted to "do this," Kurokawa couldn't leave him alone and suggests to "run away together." Not knowing where to go, the two of them jumped on a train and set off to the ocean, as Shiraki wanted to see it. Bit by bit, they established an emotional bond, but it ended all too quickly.
Several years after their fleeting escapade, Kurokawa, now working as a middle school teacher in Yokohama, reunites with Shiraki at a wine shop...
(Source: Leed, translated)