Hello thanks for wanting to help out your friend. Masturbation comes on as a result of emotional and physiological changes occurring in the body as one gets matured. There is no medical consequences per se due to mastubation but i assure you there are psychological consequences such as poor sexual life, unconscious touching of the genitals even in public areas, isolation etc. To stop masturbation, first the individual needs a strong will power. He needs to avoid staying alone, avoid watching sexually arousing movies and magazines and always try to be busy. Hope this helps. If you have further query, i will be glad to help. Best regards. Dr Achuo