Mountain doo-doo 

When you drink a large amount of Mountain Dew, and subsequently have diarrhea. Preferably, on a mountain.

"The deer were totally checking out my mountain doo-doo."

Mountain doo-doo by jimmyjimjamboree April 19, 2010

Mountain Doo 

Taking a really huge dump to learn that it all stacked on each other, creating a mountainous form.

I totally just took a mountain doo in your bathroom.

Mountain Doo by Alteffore808 August 2, 2009