When two men each fuck the armpits of a man or woman. Similar to "pit laning" but on both armpits at the same time.
by the breaker January 14, 2009
Fiend1: let's do a thriggyback!!
Fiend2: a what?
Fiend1: a fuckin thriggyback! issa three man piggyback innit.
Fiend2: oh....
Fiend2: a what?
Fiend1: a fuckin thriggyback! issa three man piggyback innit.
Fiend2: oh....
by the breaker January 16, 2009
by the breaker January 14, 2009