A condition characterized by a numb rear that is typically sore after standing up.
Gamer ass typically occurs while sitting in a chair in front of the computer for prolonged periods of time.
Over time it is believed to flatten one's ass and, in extreme cases, can lead to a concave ass (or bony butt) as the tissue and muscle begin to degrade.
While gamer ass is typically associated with gamers, the syndrome can be experienced by anyone who sits on their ass for prolonged periods of time without getting up.
P1: "I swear my ass has been getting flatter... I don't know what's happening to me!"
P2: "You're getting gamer ass. Try doing something other than sitting in your chair for 12 hours a day until your legs go numb or you'll lose that ass altogether."
The shape and size of young American men's asses from sitting on the couch eating Cheetos and playing video games all of their life. A sad state of affairs.