priapus

Doujinshi artist itto_(mentaiko)'s bara doujinshi manga inspired by the Priapus mythos in 2011.

Summary:

Zeus is sick of all the hate, envy, and violence that humans cause on Earth. So he gives Priapus the important task of making all human males homosexual, in order to destroy any means of humans to leave behind children. Priapus descends to earth, meeting his first target, Ousuke Sakura. Part 2: Priapus continues the mission that Zeus sent him on. This time Priapus ends up in rural Japan and meets his next target, Honda, a police officer.

It got so popular it even has gotten its own official English release.
From Amazon :

You can't imagine Japan's manga scene without Mentaiko Itto's amusing gay mangas anymore. Bruno Gm nder now publishes his works for the first time in English, introducing him to a broader audience.