I'm 61 years old, and when upset i bite my knuckles and joints of my fingers....just to make a little popping sound and put small painful bites in them....it takes force and takes the tension out of my hands and my jaw to do it....i make such small bites it's barely noticable. It has a calming effect on me and i have done it for many years...used to cut and do really sick invasive things to myself when i was extremely angry. Scalding enemas for example...really sick and embarrassing....i have been very ill for years.....