A binding oath made between friends to get matching tatoos. If one friend has the balls to get the tattoo then the other members of the pact must fulfill their oaths or the pact will be broken. The breaking of a tat pact results in the breaker becoming a pussy. Tat pacts are usually made while drunk or under the influence of illicit drugs. Wasted or not, tat pacts are official once hands shake.
Daniel: Yo guys, We should all get "the team" tattooed on our backs!
The Guys: Yeah dude! lets fucking do it man!
Daniel: Hell yeah, Lets shake on it.
(Hands shake and the Tat Pact is now a binding contract of friendship)