Testosterone is associated with the various physical changes occurring in the body during puberty, especially in males such physical changes include an increase in height, muscle growth, pubic hair growth, and enlargement of the male reproductive organs. There is some evidence that indicates that testosterone levels may rise during masturbation, ejaculation, which is the result of masturbation, does not significantly affects the levels of testosterone, semen ejaculated after masturbation is not the primary source of testosterone. Masturbation does not stunt growth, but excessive masturbation might affect your normal testosterone level and which may affect growth.

Masturbation is stress buster.  Use proper technique which are non traumatic and have proper diet.

Masturbation now is regarded as a normal, healthy sexual activity that is pleasant, fulfilling, acceptable, and safe. It is a good way to experience sexual pleasure and can be done throughout life. Masturbation is only considered a problem when it inhibits sexual activity with a partner, is done in public, or causes significant distress to the person. It may cause distress if it is done compulsively or interferes with daily life and activities. Consult sex therapist...