Gaming Dick is part of Fraser's relentless parody of MLG Pro Gamers. The concept largely is based on the "e-peen" phrase, but with a focus on hardcore gaming and people who take gaming too seriously in general. The phrase first originated during Fraser and Ben's Deus Ex playthrough, where they asked The Chatroom for advice on titles for the show that would appeal to Pro-Gamers and lure them in to watching the show. The resulting torrent of vulgarity bore the idea that "VGA will grow your dick" and eventually the idea of better gaming skills and increased phallus size were combined by Relkin109 who coined the term "Gaming Dick".
These days, "Gaming Dick" refers more to the level of skill possessed by a player rather than part of their physical anatomy. A particularly skilled player can be identified by a larger Gaming Dick.