I have the tailbone pain too, hurts when you’re sat down, hurts more as you stand up, then hurts more again as you’re sitting down. I’m a wheelchair user (but like to keep standing up – to make sure I can!) and I find a lumbar support (a long cushion with a ‘D’ profile) placed flat side down, along the front of my chair, so it sits under my thighs towards my knees, relieves some of the pressure on my tailbone. I also sleep on a horseshoe shaped cushion. I use heatpads during the day to ease it but nothings got rid of it completely. Regarding the pads, recently my osteopath said it’s ‘heat for muscles’ and ‘cold for bones’, so maybe I should be using cold!