An expression used to define or a particularly violent wank.
It is also used as a metaphor in any event (usually political or gang-related) where two teams are trying to constantly outdo eachother.
The act of fighting against one's partner in order to pull the chew toy from them causes a very pleasurable sensation for one's genitalia, and growling and snarling with bared teeth can uniquely heighten the moment of orgasm, and contribute a primal, bestial quality that is far too often missing from everyday sex.
The act can be performed heterosexually or homosexually.
"I always wondered why my boyfriend kept a dog's chew toy in his room when he never had a dog. After we played Tug of War last night, I understood."
"I ripped out a tooth last night playing Tug of War."