When you are bored on a road trip with a group of people, and you drink a large amount of prune juice. Long story short, whoever has to make a bowel movement the first, looses.. no dual action cleanse required!

the key to cheating is to eat a bunch of bread before ingesting said laxative liquid beverage.
Your on the road and one person says "Hey guys, lets take the prune juice challenge!" ..
by TyBong - Anoka, MN March 28, 2009
Get the PRUNE JUICE CHALLENGE mug.