Lit.;Shit Soup Technique
A one-shot bara manga by Yamakawa Jun'ichi, released in 1987.
Two gay men, the young Masaki Michishita who is sensitive to handsome men, and Takakazu Abe, a car mechanic who's sitting on a park bench, engage in one of the most iconic encounters in eromanga history and end up having sex in a bathroom stall.
Due to the memorable quotes and reaction faces, the manga later spawned the "Yaranaika?" meme in 2002. These memes and resulting interest in the manga itself would spark a boom in yaoi and yuri content that continues on to this day.
It is often paired with Manatsu no yo no Inmu (Inmu-chu) and gachimuchi as the "Holy Homo Trinity" (御三ゲイ), since all three were well-known homoerotic memes that were popular within Japanese communities in the 2000s.