A word invented by =WTF= members of the America's Army multiplayer FPS online game. It is the act of inserting your scrotum into an enemy's mouth after being shot, blown up, thermited, etc... Especially funny when they land in precarious positions, when they are acting like bitches, a noob, or even more funny when they are part of the same clan. Even more funny when you let the receiver of this ungodly act know that you forgot to wipe, forgot to shave or purposely shaved your nuts, or any other variation of scrotum modification.
"LOL, hey Baz I just T bagged that fucking noob Dr. Spray and he enjoyed it, what a homo!"
"T-bag, have some borg salted nutz!!"
"Check out this noob with his second account, let's TK him and the have a T bag party on his dead body!"
Source: =WTF=RiflemanRuss, USA, CA (come get some bitches)