In the past, when I have been on a major alcohol bender, I have cut myself, only a couple of times though. Once I smashed a milk bottle over my head.
I can remember cutting my wrists, like 'practice' as you said. I have not done it sober but I imagine some of the feelings I got when doing it are similar.
Basically, you need help with this Hippy. I remember you are have a pyschiatrist, I think? Do they know?
Please try not to do it...