I can relate to the trigger part you wrote. Very intense impulses. Very violent. I know these thoughts are totally whacked, but that doesn't stop them. (Though thank God it's stopped me(!)) But what I wanted to say is that one thing I did when I knew I just couldn't do that, but was totally compelled to do something, was ... And this is going to sound silly... took a marker and wrote on the bottom of my feet.

The weird (or maybe it isn't?) about those impulses is that I'm not even like, at ALL! Totally squicks me out and I don't "get" it. And yet, there's my brain flashing

Bad self-harm trigger

Anyhow, yes, marker. A MUCH better option! I did that for a few days (conveniently, it wears off, so one may repeat, or come up with some other terrible thing to say) until it worked out of my system and I was no longer inclined to do it.