Provided is a sleep aid for use in reducing the risk of plagiocephaly including a cushion and a sleep position indicator. The cushion includes an elongate pad to accommodate a person in a reposed position such that the person extends along a longitudinal axis of the pad. The cushion also includes a casing surrounding the pad that has bottom and top panels. The sleep position indicator has an elongate dimension and is slideably supported by the cushion. A medial portion of the sleep position indicator is adapted to move transversely to the longitudinal axis within a slideway. The indicator may be moved between a first position where it visibly protrudes from a first side of the cushion to inform a first head orientation, and a second position where it visibly protrudes from a second side of the cushion to inform a second head orientation.