A dump stack is achieved by eating a meal that pushes out a lingering dump in your innards. The pressure on the existing dump caused by the ingestion of the meal gives the push needed to clear things out.
by danyo March 26, 2005
When a person gets on a toilet to defacate, only to be sat on top of by another person who defacates between his or her legs. There are three variations: standard, where both people face forward; the side-saddle, where the top person sits like a child on Santa Clause's lap; and the reverse, which allows the two people to make out with each other while defacating.
Jim: "So last night after my girl and I finished making love, I went to the bathroom to relieve myself, and she in her passion joined me in a dump and stack to further prove her love to me!"
Brandon: "Jim, what the FUCK..."
Brandon: "Jim, what the FUCK..."
by Kamui Takahashi September 29, 2009