stfupcake Share definition Flag Often used to counter failcake, a stfupcake is a word used to tell someone to shut the fuck up. Paige: "You got ownt! Have some failcake!" Zano:"Why don't you have some stfupcake?!" stfupcake by betterknife06 April 11, 2009 0 0 Get merch Get the stfupcake mug. Buy Now — $32.95 See more merch