This is an important point. And one that I should have mentioned the other day. People commented about particular types of fits that we ought to talk about, and I have examples of some other kinds of fits that are worth considering.
There are two basic categories of fits, as far as I'm concerned: healthy fits and not healthy fits (and there's of course a continuum- since things in life are usually not black and white...).
Healthy fits can be described (at least in my view) as expressions of energy that do not hurt us or anyone else. In the healthy column we have things like talking to a friend- or talking loudly to a friend like I did the other day; punching a pillow; tearing up a phone book; crying; bouncing a ball really hard; stomping around the living room; yelling into a canyon... (obviously these need to be done in ways that are not harmful to you or to others... so keep that in mind- that's in my definition of a "healthy fit")
Not so healthy fits are expressions of energy that are harmful to ourselves and/or others. In this column we have things like cutting or burning or other self-injury, purging, hitting ourselves, overexercising when we are injured or malnourished. Basically, these are examples of Internal Fits, which a couple of you guys mentioned.
These not so healthy fits are understandable- when someone wants to be the perfect girl or boy and not "cause a ruckus" or get in trouble, they don't allow themselves to express energy outwardly. That energy has to go somewhere (physics, folks) so it gets directed inward. This may work short term (although even then it's costly to us humans) but it sure is damaging longer-term.
SuperEgg asked about what to do when you feel like you keep having to having internal fits because there's no other option. That's a tough one. I think the first thing I'd say is to ask yourself: do I really, really, really need to keep it internal. And to seriously challenge yourself on that. And if the answer is Yes, then you need to look for other outlets for the energy- if it can't get expressed directly and outward, which is ideal, perhaps you could find other ways that aren't quite as direct but also aren't straight up internal. I'm thinking- something like writing or painting or sculpting or singing... just making this up as I go along. You wouldn't have to write about the exact thing the fits have to do with if that seems to exposed or scary. You could sing about what a fit is or what a fit feels like or the color a fit appears to be... or you could shoot basketball hoops and every time you shoot you could imagine that action being your fit... play around with this and see if you can come up with actions that can serve as your fit. These types of actions can function pretty well as a fit- and no one will even know you're having a fit- so you dont' have to worry that you're causing a ruckus or might "get into trouble." But first, of course, have a talk with yourself about if the fits do need to stay internalized.
Healthy fits are expressive, expansive, life-affirming. Not so healthy ones are constricting, confining, life-squishing (yeah, I couldn't think of the opposite of affirming, so...).