Ah I love Gamsol and Prisma Colors! It was today's Technique Challenge. The first shot is a picture of what the pumpkin looked like before I swirled on the gamsol with the paper stump. It looks horrible, but once you start swirling you get smooth perfectly blended colors.
The tutorial on this is awesome and I highly recommend checking it out and giving it a try. If you don't have Primas, just grab some colored pencils and you can substitute baby oil for the gamsol.