An apparatus is configured for use with a chair having a supporting surface, and includes a cushioning member adapted to be placed above the supporting surface, a bottom sheet connected to the cushioning member and having an engagement surface opposite the cushioning member, a top sheet having a bottom surface positioned in confronting relation to the engagement surface and a top surface opposite the bottom surface, and a selective gliding assembly positioned between the top and bottom sheets. The top sheet has at least one end connected to the bottom sheet, and the top sheet further has a slip resistant material positioned on the top surface. The selective gliding assembly includes engagement members positioned on the engagement surface and on the bottom surface of the top sheet, and the engagement members engage each other to resist forward sliding of the top sheet and to permit rearward sliding of the top sheet.
