Here is how you do it: I used a blend of Premo! white and Premo! Ecru, with just a hint of yellow. I created a very, very soft lump of clay by conditioning and warming with my hands. Once I molded the clay into the organic shape I desired I took a knitting needle and swirled, whipped, and whirled the inner and outer edges. Think of whipping cream (just not as aggressively) on a smaller scale! You should press into the clay and create circles while pulling upward to give the "ruffled effect."
Once I complete my desired effect I allow the clay to sit for at least an hour. This gives it a chance to firm up. I then used various inks and pastels on this one to give it the worn palette.
This is such a fun technique and I hope you enjoy creating your own organic designs with this helpful little texturing technique!