A coccyx cushion is a tool used specifically to help with sciatica. It is thought that the coccyx can cause sciatica if it becomes too damaged or aligned wrong. If this happens, the person may feel pain and discomfort when sitting down and moving around which can make long-term use difficult. What is the Purpose of the Coccyx? The coccyx is shaped like a pear. It is designed to help attach your muscles to support the spine. It doesn't perform any other functions but this is what makes it so interesting! This vertebra does not provide you with many benefits and is only used for providing support for your spine.