the double volcano surprise is when you put mentos and diet coke in a girls vagina, and baking soda and vinegar in her anus. thus causing a chemical reaction, which shoots "volcanic" liquid out of the said holes. it isnt much fun for the girl, but it sure is fun to watch.
John gave me the double volcano surprise last night, it hurt so bad!
by lieutenantURNER September 03, 2008