An orthopedic donut chair cushion, also known as a coccyx cushion or tailbone cushion, is a type of cushion that cushion designed to provide support and relief for the tailbone and surrounding areas. some common uses of an orthopedic donut chair cushion include: Relief from tailbone pain(coccydynia) or discomfort. Reduced pressure on the tailbone while sitting. -improved posture and sitting alignmen