The fourth wheel's job is to make sure the third wheel doesn't step his boundaries as a third wheel.
Girl: Hey, I've noticed that John has trying to cheat with me lately. Should we invite Henry to fourth wheel for us?
Boy: Yeah, I think John stepped his boundaries. Ill call Henry now.
Boy: Yeah, I think John stepped his boundaries. Ill call Henry now.
by Celestivic April 9, 2017

by The Return of Light Joker October 19, 2009

by Noctrl May 26, 2006

by Maxima September 7, 2005

To form a circle and sing Wagon Wheel by Old Crow Medicine Show while passing a bottle of booze around until its contents are consumed.
by Portlandiaisreal September 1, 2013

by Red Swingline Stapler May 10, 2007

by Coloradoislegal October 16, 2010
