A device for use with a bed having a frame and a supporting surface includes a flexible sheet with a tether strap connected to the sheet and extending from the sheet. The flexible sheet has opposed top and bottom surfaces, with the top surface having a high friction material with a higher coefficient of friction as compared to the bottom surface, which includes a low friction material. The tether strap is configured for connection to the frame of the bed to secure the sheet in place. A system incorporating the flexible sheet may also include an absorbent pad configured to be placed on the top surface of the sheet, where the high-friction top surface resists sliding of the absorbent pad, as well as one or more wedges having a base wall that the wedge rests on and a ramp surface configured to confront the sheet when the wedge is placed under the sheet. The base wall and the ramp surface may also contain high friction and low friction materials, respectively.