When man is hungry.... he eats food and makes himself happy. Similarly when man gets sexual feelings...he needs to get satisfied by doing sex. Since sex is not possible with a female before marriage, man substitutes sex with masturbation. It's good for health as it satisfies you when yo get intense desires to adolescents or young adults before getting a sexual partner. When done ....semen 3 to 4 ml goes out. Many feel loosing semen that way is not good for health( misconception) which is not TRUE. Doing masturbation one or 2 times in a week is not bad.