A coccyx cushion is a pillow that you place under your tailbone so your spine curves, and it can be used while sitting. The pillow helps to relieve pressure on the pubis bone, which often causes irritation or pain in individuals who suffer from tailbone pain. It also helps to relieve pressure on some other parts of the body, like the lower back and hip area. You can use it while sitting at your desk chair during the day, and while sitting in your bed while you sleep.The coccyx cushion can also help to relieve pain that is exacerbated by sitting or sleeping on an improperly positioned pillow.