A fork of Rural Dictionary
For N people n1, n2, n3... ...nN, if n1=n2 and n2=n3... nN-1=nN, Then n1=nN, where = can be verbalized as 'is butt fucking.'
If Preston is butt fucking me, and I'm butt fucking Eric, by the Transitive Property of Butt Fucking, Preston is butt fucking Eric.