When you accidentally plug two banana plugs into the same hole. Other wise known as the mating ritual of the consenting adult banana jack.
Kirt was double jacking it this morning and messed up his equipment!
by Clive&Cleetus May 10, 2007
1 more definition
A fat chic being penetrated by two men in the ass and vagina. Since she is fat and usually disgusting, but willing,the men work fast to get it over with.
Fat susan ask bragged about her doublejacking. Shes been much happier ever since.
by mori10 February 16, 2008