Masturbation
Masturbation for males is the act of stimulating the penis, usually by hand, to provide self-pleasure. For teens and adults, masturbation usually ends in what is called an ejaculation (the release of liquid called semen which contains sperm cells). This ejaculation is usually accompanied by a powerful, pleasurable feeling called an orgasm. Most boys start masturbating between the age of 10 and 15. It is not uncommon for younger boys to do so, even if they cannot ejaculate semen. Even male fetuses in the womb sometimes appear to play with their penis.