Using a single strand of one hair color about 3ft in length, secure and start on one end (I typically choose neck). Start stitching at random along the back of the caterpillar till you reach the tail. Try to place the stitches at an angle so that the distance between each stitch on the back is minimal.
Repeat with the second color.
Do have some fun with this. I literally do mean be random! I’ve made multiple caterpillars, and despite having a pattern, no two have ever looked exactly the same.