A non-rigid device, usually made of flame retardant fabric and/or polyurethane foam materials, intended to modify the sleeping position/posture of infants to prevent deformational plagiocephaly, a flattening of the back of the skull from a consistent back-sleeping position. It is available in a variety of designs including a wedge-shaped head pillow, a sleeping garment (sleeveless vest) with hooks/Velcro fasteners/nylon zip fasteners and an insertable foam wedge, or a specially designed mattress. This is a reusable device.