Coccyx Car Cushion

Cushion is soft and comfortable. I weigh 142 pounds. When I sit on cushion, my weight pushes the back of the cushion too low and my coccyx just about touches the chair. This defeats the purpose of the cushion. Perhaps the back should be 4 inches in height, and not just 3 inches. Or, the pillow could be a tad firmer. Still the is brand is better than most brands.