"Gachimuchi" is derived from two Japanese terms: "gacchiri" (がっちり, "muscular", "athletic"), and "muchimuchi" (ムチムチ; "chubby", "throbbing").
In Japanese sources, "Wrestling (Series)" (レスリング （シリーズ）) is used more often.
On September 30th, 2007, a video clip from Billy Herrington's video, "Workout Muscular Men 3", was uploaded to Nico Nico Douga as a bait-and-switch video, as "Professional-Pants Wrestling" (本格的 ガチムチパンツレスリング, Honkaku-teki Gachimuchi Pantsu Resuringu). It nonetheless gained more than 5.5 million views in less than five years, and spawned many musical remixes and comedic edited videos involving him and other characters, under various tags, such as "Gachimuchi Pants Wrestling" (ガチムチ パンツ レスリング), or simply "Wrestling (Series)" (レスリング （シリーズ）-- the tag most-often used by its Japanese fandom), "Forest Fairy" (森の妖精, Mori no Yousei) and "Philosophy" (哲学, Tetsugaku -- commonly used by Chinese fanbase).
At some time within its early years in Japan, the Gachimuchi fandom had a strong rivalry against another fandom that made parodies of poorly-made homoerotic videos that were known as "Manatsu no Yoru no Inmu" (真夏の夜の淫夢, "A Midsummer Night's Lewd Dream"), or simply "Inmu" (淫夢) for short. That playfully-creative fandom, known as "Inmu-chu" (淫夢厨, an insulting term), was notable for being among the most popular fandoms in Nico Nico Douga, but was also notorious for fans who behave as nuisances. Some videos were drowned in waves of nauseatingly-colored comments that consisted of flame wars between Gachi fans and Inmu-chu.
Nonetheless, it became popular in the United States (where its source videos originated), due to local audiences being amused by the sources and their characters depicted in bizarre ways. Ever since, it has gained audiences outside Japan, in other countries such as Taiwan, China, Russia (as shown in Youtube videos and comments in the American section for Nico Nico Gachimuchi source videos), Poland, and Ukraine -- whereas its Inmu rivals have been relegated to Nico Nico Douga and Japan due to a lack of interested foreign audiences.
It was also used by the Swedish Hearthstone gamer, Forsen, in some of his videos and in his Twitch account, in which he sometimes speaks and messages to Billy Herrington on Twitter. However, due to his usage of Gachimuchi memes being limited as something akin to a background prop, his version of Gachimuchi did not enjoy the same level of popularity that allowed Gachimuchi to earn foreign audiences, but only to be relegated to being cheap memes.
- Gachimuchi is also a name for a subgenre of "boys love" or "bara" (薔薇, "rose"), an art or fiction genre involving homosexual characters. Among English-speaking fans of the subgenre, it is referred simply as "bara".
- "Gachi" also resembles the Japanese word "kachi", which means "victory", or the suffix "-gachi", which means "able to do" (both are written as "勝ち").
- Some aspects of Gachimuchi, especially in the Japanese fanbase, were influenced by the Inmu fandom, such as one of Van Darkholme's nicknames being "TDN" due to his resemblance to an Inmu character.
- Just as annoying Inmu fans are called "Inmu-chu" (淫夢厨), annoying Japanese Gachi fans are called "Resuringu-chu" (レスリング厨) or "Re-chu" (レ厨)
- As much of the sources for Gachimuchi were from gay pornography videos, many scenes in the videos had to be cut or censored, to comply with the rules of the websites that these videos are being posted in.