In a large bowl mix the peanut butter, light corn syrup and powdered sugar together until well blended.
Then add in the dry powdered milk mix one cup at a time. Knead with your hands until smooth. You may not need the whole 3 cups. Check your dough after 2 cups and add more as needed to reach the right consistency of playdough.
Notes
(Its' a little greasy because of the peanut butter so we made sure the kids played on a safe surface such as the kitchen counter or table.)