When a person accidentally poops while mooningsomeone, and the smell of their own feces causes them to make the stank face.
Cheryl had diarrhea, but had the sudden urge to moon Josh. While mooning Josh, Cheryl started to release her feces, and the smell caused her to express the stank face. And Josh experienced the full effects of the StankButt.
Nickname given to bales of marijuana thrown overboard or out of airplanes. Origin is reportedly from members of the US Coast Guard in the area of Southern Florida.