Which side of the pillow do I sleep on? August 06, 2019 14:32 The pillow should be placed “cap down” against your mattress. Related articles Chiroflow's Product Quality Assurance: How do my patients fill the pillow? What type of polyester filling is used in the Chiroflow pillow? Is Chiroflow hypoallergenic? What is the size of the Chiroflow® Professional Waterbase® pillow?