My experience is that pain from pressure on the tailbone is very common among CES patients. Doing everything possible to prevent irritation is preferable to what can be rather a long recovery. My best day to day solution is to invest in a very good wedge-shaped cushion that has a cut out in the back which avoids pressure on the sensitive coccyx. No all of these wedge seat cushions are created equal; upholstery weight foam that doesn't flatten out after a short length of time is essential. I keep one in the car at all times, carry one into doctor's offices or anywhere that requires sitting and waiting. I consider them an absolute essential for taking into restaurants and I keep one on hand at home for use on any hard chair. Look for one that has good depth in the back and that does not flatten out in use. Those with a cross piece across cut-out are allows one to carry them in a way that avoids drawing attention. A bonus is their use in a car; most car seats cause pressue on the coccyx as well as on the back of thighs during long trips, causing numbness and muscle spasms. -- By the way, price is not a good indicator of how well the cushion holds up over time. I wasted a lot of money until I found one recommended by a very large truck driver - he had used the same cushion for years and I have had the same experience....and at a lower price than previous cushions. There is also a thick foam cushion made for wheel chair use that I find helpful. They look almost like a block of brownie's that have been cut into squares. each square acts independently so pressure on those nerves changes with every move. -- I find it best to prevent pain from taking hold and having these two types of seat cushions have made my day-to-day life with CES easier.
I feel your pain so hope these suggestions may be of help.