I wasn't abused, so maybe I shouldn't be replying, but I just wanted to let you know that I do that sort of thing as well. I thought I was the only one! They're mostly to do with guns, but the earliest one I can remember was about me falling on broken glass when I was in primary school...I can't remember how old I was exactly.

I hate it, and it scares me sometimes, but I do it anyway...I don't know why I don't just stop.

I'm not sure if my reply was at all helpful, but you're not alone.