アッー! (Aaa!) is the scream Billy Herrington makes when Danny Lee grabbed and crunched his crotch at Workout: Muscle Fantasies 3. It is one of the most notable memes in Gachimuchi.
Before Gachimuchi, it was also made by one of the characters in Kuso Miso Technique. Japanese Gachimuchi fans commonly use the アッー! scream as a pun in many names, including parts of Shinnippori.
In America and western countries, it is known as "Gachigasm".
