I have done it. Pucker up baby because I have made the most toxically sour milkshake / Smoothie on the planet earth. I used so mach sour candy it's insane. Sour Patch Kids, Sour Skittles, Warhead everything, Sour Gummies, lemons, EVERYTHING. It did not turn out delicious...at all, but it did turn out CRAZY SOUR! Mission accomplished.