Abstract: A bolster for resisting rolling of a person off of a mattress, comprising a lateral cushion adapted to be disposed proximate and parallel to an edge of the mattress, and a tensile portion having a means for attachment to said lateral cushion, providing a distributed tensile force to resist a laterally outward displacement of the lateral cushion, the tensile force being transmitted beneath the mattress having a force vector downward and inward. Both the lateral cushion and the mattress may be inflatable, and preferably a pair of lateral cushions, interconnected by a tensile sheet below the mattress, are provided.