GachiBass is a Twitch emote from BetterTTV showing an image of muscle man Billy Herrington. In the image, he is shown looking into the distance in satisfaction with his eyes closed. This emote is predominantly used to show pleasure or satisfaction similar to other emotes of the same category.
The emote originated from a Billy Herrington wrestling remix that was originally posted to plug.dj, a social music streaming site. After gaining some traction it was then adopted by the infamous Forsen community where it then started its ascent to infamy.
On October 13th, 2015 the GamesPlace Youtube channel uploaded footage of Forsen playing the game Hearthstone. The video was titled “Forsen – gachiGASM” where viewers spammed the emote in chat.
After being posted so many times in various live streams and threads it was officially banned in /r/forsen. This was when it officially took off, since being banned in a popular subreddit makes it controversial which in turn makes it much more popular.
After that, it was just pure momentum and eventually became a familiar emote amongst all the popular streamers. After being picked up and gaining traction in most, if not all, popular streamers, it cemented itself as an extremely popular emote amongst Twitch.
The streamer that you are following either intentionally or unintentionally does something extremely satisfying. Deploy the gachiBASS.