You can control your subconscious with commands. For example I got rid I biting my nails using this method.
Say "Stop biting my nails. 10x and the last time yell it in your head and scrunch your body together.
Say "Quit biting my nails. 10x and the last time yell it in your head and scrunch your body together.
Say "Don't bite my nails. 10x and the last time yell it in your head and scrunch your body together.
Do this 3x per day until it goes away.