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 What type of polyester filling is used in the Chiroflow pillow? Is Chiroflow hypoallergenic? What should I do if a patient returns a pillow to our office due to a warranty issue? What is the size of the Chiroflow® Professional Waterbase® pillow? My pillow is leaking, what do I do now?