Don't. That's how you do it. Don't ever start. If your brain is stopping you, take it as a sign and listen. Self harm is hell on earth, it does nothing but make everything so much worse. You will deal with the shame, the guilt, the anxiety of having to hide it all the time. Whatever situation you're already in, self harm will not in any way shape or form help it. It will get worse and worse as your mind starts to crave more of an endorphin release that the initial cuts no longer give it. Next thing you know you're cutting deeper and deeper, or you're switching to other methods. I've nearly taken limbs off before. I microoverdose on meds daily and I am constantly in pain because of it. There are people who become anemic. People whose cuts get severely infected. Your family or friends find out and now they don't see you the same. The scars could ruin potential job opportunities. You hate yourself for it but you can't stop. Self harm is not something to "try out". If your mind it telling you not to do it then listen.