I just pinch any bag of stuffing between my fingers, and rub then together. The stuffing will either slide back and forth as if lubricated, or it will not slide well. The stuff that slides the best will be less likely to bunch and become lumpy or flat with use. I learned that from Eleanor Peace Bailey, (a world famous custom doll maker and writer), that she discussed at a seminar she held at a local store. I hate when pillows or "stuffies" go flat! Price is not always a good way to judge this product. Some of the worst lumping stuffing I have bought was the more expensive.