These bastards are painful, and can in some cases cause infections, although generally bits of broken off spine should work their way out naturally. It’s a good idea to try and get them out the same day you got them though.
First of all, soak the urchined area in a bucket of hot water with soap in or bleach (not too much). Your skin then gets all wrinkly pretty quick. Then try to prize out the spine with some long tweasers and a pin, in the same way your mum used to with a wood splinter. If you find you’re pushing it deeper, adjourn until a later moment. Once you’ve worked
that uncomfortable calcium carbonate needle out of your body, which will feel pretty good, be sure to disinfect the whole area with alcohol/Chinese medicine. And should you be one of those unbelievably unlucky people we hear about from time to time that get urchins in their undercarriage, well we’d recommend you stop reading this and seek immediate professional medical help.