I've had coccyx pain for the past 4 years and must have tried almost everything available to alleviate the pain and function normally - cushions, rubber balls to sit on, ergonomic chairs, standing desks, ganglion impar blocks etc etc. I need to take the bus several times per month and that became excruciating at one point. The one thing that worked for me is this: Backjoy.
It's not terribly comfortable to sit on for extended periods (even though I do it anyway because it eliminates my pain), but it pushes your butt together and, because it's hard and concave under the coccyx, it elevates the tailbone from whatever surface you're sitting on. For me, it has worked really well and I can sit on chairs and also travel pain free when I use it.