when three men/women put they're butts together as a male puts his penis inside and out them again and again until the male has to ejaculate, as he aims for the middle
A: I heard dave got lucky at the party B: I heard he had a CrackTriangle with three women
A: Nice!
3 people half bent over forming a triangle with each persons face at the person in fronts Arse. At the same time each person shits in the person behinds mouth.