Self Hypnosis does work...I have done it a number of times.
You can not be hypnotised against your will.
You can not be made to do things which you would normally not do.
You are conscious and in control of your own will.
Think of the last time you were going to sleep. Remember just as you were falling into it, that period when you were conscious of things around you, but they seemed like a dream to you. This is as close to the Hypnotic state.
It has alot of uses. I can be used for helping people who want to be helped.
The more they want it the better the effects from the attempt. But in most cases the post hypnotic suggestion needs to be done again within a few days to a week for lasting benefits. I would suggest you look at the page linked by Larry.
PS...I learned this in High School. My Gothic Lit teacher trained us all in how to do it. Some of the parents went nuts and took their kids out of the class. They thought she would turn us all into satan worshipers. Of course she also taught us to read Tarot Cards and Numberology.
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The line between good and evil is razor sharp. Be careful of misteps,
lest you find yourself spitted upon your own blade.