Masturbation is very much a stress reliever for either sex. This will, of course, depend on the individual's belief structure. If the individual feels they are doing something wrong, than, there would be added stress. This idea of 'wrong,' however, is an incorrect assumption. Non the less, it would create stress because the individual would feel that they are 'wrong,' and cannot control it. Once again THAT IS AN INCORRECT ASSUMPTION.
One of the functions of masturbation is the direct relief of sexual tension. It also has a way of 'grounding' and producing other chemicals in the body allowing the individual to relax.
With Regards,
Daniel