I've been a cutter since my early teens and still have the thoughts when I'm down and depressed. I don't think you can ever get to old to not have these thoughts. I try to preoccupy myself (thoughts and hands) with other things that are less destructive.

No one seems to understand that I like the pain and the relief it brings. I've tried to do other things like click a pen, squeeze a stress ball, do things with my hands. But I tend to fall back into slightly more destructive habits like ripping off the skin on my lips, pulling out eyelashes/eyebrows, snapping a rubber band on wrist until it splits open the skin.

I know this isn't all that useful but my best advice is try to preoccupy yourself with out thoughts and behaviors... trust me, it's hard to do.