"Stamping on soil" or "kneading soil" is an ancient technique for preparing soil, involving mixing large quantities of two or more types of soil. Before stamping, the area where the soil will be piled should be cleaned to prevent stones or leaves from contaminating the soil to be kneaded.
Once the area is ready, pile the soil in the center. Gradually use your heels and the sides of your feet to knead the soil from the inside out. The spacing and pressure of each step should be consistent.
Once the soil has been spread out into a wide, spiral-like pattern, approximately 3-4 inches thick, pile it back into the center and begin kneading again. Repeat this process 4-5 times, or until the soil is well mixed.
Once the soil is prepared and mixed, it can be cut and used to create various desired pieces.
Note: In these sample photos of soil stamping, SOC: School of Ceramics by Pottery Clay used Terrapot, Celaton, and LightClay mixed together.