DGD is an abbreviation for the phrase, "Doing great, Damiani." DGD is often used in Twitch chat as positive affirmation for when one of the Allies completed something challenging on stream or is progressing well in a game.
The term DGD was first coined during the Silent Hill 2 Stream Team featuring Damiani, Ian, and Huber on January 15, 2020. Damiani was playing Silent Hill 2 for the first time while Ian and Huber supported him as veterans of the game. Throughout the stream, they would keep repeating variations of the phrase, "Doing great, Damiani" as a sign that he was doing well for his first time playing.