How do I prevent myself from masturbation

If you are with me you won't have to masturbate;)

Wear boxing gloves. :-)

Just think: Gods watching you do this....
Besides, why don't you want to masturbate? Do you do it too much? Did you get caught? Were you ashamed?

You can keep yourself busy doing other things...

Also:

http://www.betterhealth.vic.gov.au/bhcv2/bhcarticles.nsf/pages/Masturbation

How much is too much?

A common concern, especially among young people, is the frequency of masturbation. ‘Normal’ ranges from several times per day, week or month to never masturbating at all. How often a person masturbates isn’t a problem, unless it’s linked to an obsessive compulsive disorder where the same activity must be repeated over and over.