Tailbone

Did you fall on it?
Arthritis?
It is the lowest part of the spine.
It doesn't need "care" except to keep it from injury.
surrounding muscles and/or nerves going thru the same area can cause pain.

As far as I know, "tailbone" is merely nickname for the coccyx. I have heard from friends who have bruised or broken then (often ice-skating or skiing) that a sore tailbone is REALLY sore. The broken variety requires great care and styill takes some time to heal. If your coccyx is bruised, it might hurt so much that you assume it's broken. Only a doctor (with a radiologist) could differentiate. If there's any doubt in your mind--break v. bruise--please find out right away, as you might be stalling the healing if it's a break.
The only palliative measure that I can remember my friends' using is avoiding hard seating. Easy to do with pain like that. There may be further instructions about posture, but I'm not a doc. I do know that, if it's broken, you cannot heal it yourself at home; also, it would be a major bummer were it to heal crookedly because you have ignored it or refused to get professional medical advice.

http://en.wikipedia.org/wiki/Coccyx

http://www.nlm.nih.gov/medlineplus/tailbonedisorders.html

http://www.webmd.com/a-to-z-guides/tailbone-coccyx-injury