When in a group of people, a silent fart is made by one of the group. Invariably, the smell produces the "Who did that?" quote. When the offending person admits to it, one or more people will let silent but deadlies go, knowing the original offender will be blamed. Thus, the piggy back fart.
John farted and a couple of us piggy backed on that shit.
by Joe April 10, 2005