Similar to motorboating: The placement of one's face, specifically the mouth, into the area between ass cheeks followed by a rapid shaking of the face in a side-to-side motion accompanied by yelling.
Joe found Brad Pitt so hot that he wanted nothing more than Brad sit on his face while septictanking the hell out of him him.
by GfDew July 16, 2009
Get the Septictankingmug.