The natural act of a man dipping his ball sack into either a woman's or defeated opponents mouth as if it were a Tea-bag.
Most often used in the gaming community as a victory move. After you kill an opponent you highly dislike it is not uncommon to stand over your enemies lifeless body and crouch up and down over and over in a T-bagging manner while the opponent watches from the kill cam his body being defiled. (Note: Although uncommon T-Bagging a player while in a laying position such as sniping can also be done and is extra funny for the kill cam review.) Note that T-Bagging can get you spawn killed or verbally assaulted over the microphone.
"The gamer finally killed his opponent after many spawn kills and took his revenge by T-bagging the body of his downed opponent."
"Did you see that asshole? He just T-Bagged my body! Everyone spawn kill him!"