Abstract: A seating orthotic cushion comprised of an elongated wedge of resiliently deformable material having a substantially planar top surface, a front surface meeting the top surface, and a bottom surface comprising a plurality of planar portions extending side-by-side from the front of the cushion to the back, the portions meeting in such a way that the bottom of the cushion slopes progressively upward toward the top of the cushion on either side of a line substantially bisecting the cushion between its sides. This seating orthotic cushion preferably includes a waterproof cover having a high coefficient of friction, and filled with an organic foam material.