For a while I used to hit myself on the fat part of both thighs with a rubber mallet, whenever I felt I had screwed up at work or school or in my personal life. I guess it was a crude attempt at aversive conditioning that absolutely failed to change anything.
The "good" thing about this method is that it left no permanent marks, hurt like hell from first to last and as far as I could tell could do no lasting damage. Yes, it did leave red marks and occasional bruises, but they were all on a body part I never expose to public view, and all bruises and marks faded over time. (Perhaps I could have burst a capillary or some such thing, but never did. I'm candidly unclear what the result of that would have been.) I also never developed any of the sort of desensitization to the act I understand cutters do. IOW, I never seemed to need to do more of it to reach the same level of pain over time.
The "bad" thing about this method is that, first, it took a bit of time to finalize. I started doing it not with a mallet, but with a 16 oz. steel hammer. And did it to my stomach area. Steel is harder than rubber, stomachs are a lot more sensitive than thighs and hammers have a relatively small head, meaning a greater concentration of force with each strike...all nicely highlighted for me when I started vomiting what appeared to be pure blood shortly after starting this regime. So that method was out. Fortunately, it didn't take much additional thought to come up with the "final" method, described above. The other bad thing is that I always ran the risk of discovery. The sound of mallet on thigh is surprisingly loud, rather like tenderizing meat. Fortunately my ex-spouse never really caught on, though I know she heard me at least twice.
I stopped not because it wasn't working as I hoped in changing my behavior (even though it wasn't) but because I carried things a bit too far one day and hit myself 40 times on each thigh. I could barely walk up the cellar stairs and then involuntarily collapsed once I was in the shower. My legs literally could not hold me up. Fortunately I recovered enough to stand in five or so minutes, but figured I'd take a break from doing this.
That was about four years ago, and I'm now reconsidering. I'm not sure I will start again, but I'm not sure I won't. I am obviously such an absolute eff up that SOMETHING needs to be done. And these suckers are only a few bucks at any hardware store:
"Wherever pounding is required." Couldn't have said it better myself. 
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"The man who has fed the chicken every day throughout its life at last wrings its neck instead, showing that more refined views as to the uniformity of nature would have been useful to the chicken." ? Bertrand Russell