According to Wikipedia the masturbation (M...) refers to sexual stimulation, especially of one's own genital and often to the point of orgasm, which is performed manually, by other types of bodily contact (except for sexual intercourse), by use of objects or tools, or by some combination of these methods. M... is the most common form of utoeroticism, and the two words are often used as synonyms, although M... with a partner (mutual M...) is also common.

When you were really little, you may have learned that touching your body makes you feel good. A lot of you have probably stopped since then. M... involves touching your penis or your clitoris, vulva or vagina in a way that gives you sexual pleasure. Exciting sexual thoughts fill your head, and, if you go long enough, you'll probably have an orgasm (rhythmic muscle contractions that produce a feeling of pleasure). M... is a great way of giving yourself sexual pleasure, getting to know your body and what you like sexually, or just to burn off some sexual tension. It's also completely harmless, and can give you a lot of sexual pleasure without the risk of pregnancy or getting a sexually transmitted infection.
These days, most people don't see M... as "wrong", provided it's done privately. But some religions may call M... immoral or a sin, and some parents may frown upon it. M... is a great outlet for your body's sexual responses, but you're free to practice it or not. It's your choice, and it's completely up to you. If you are comfortable with it and you want to do it , do it. Just find a private place and a time when you're not going to be disturbed and give it a try. If you don't want to do it or you think it's wrong, that's perfectly fine too. The truth is, each person is different and each person has to decide for themselves how they feel about it. But one thing you should know is that M... is very common and isn't going to harm you.
Guys usually do it by stroking and rubbing their penis, while girls usually rub or press around their clitoris with their hands or a comfortable object. Fantasizing about something you find sexy may also help to enhance the experience. It's perfectly okay, and it's a great way to add to the pleasure of M....
How you do itis a matter of whatever feels right for you - you can't do it "wrong". You'll probably find that you get better at it each time you do it. There's also no such thing as too much, but you might get sore if you rub a lot. And no, you won't go blind, you won't grow hair on your palms, your hands aren't going to fall off, and there is no such thing as a man running out of sperm. M... also will not hurt your sexual life later on. In fact, the things you learn about your own body now may actually help you be more comfortable when you decide you are ready for intimate relations.

It may seem like guys talk about M... a lot more, but it isn't just for guys, and it's not weird to be a girl who enjoys it. Millions upon millions of women do it. In addition to being really pleasurable, some women may not reach pleasure as easily as men, and M... is a good way for a woman to "practice" getting there. Knowing her body and knowing what feels good may help make love better for her and her partner in the future. But again, M... is your choice to make. Do it if you want to, and don't if you don't. Some women may also do it to the point of sexual leasure as a way of soothing cramps during menstruation. Others, though, find that M... can make cramping worse.
Think of it this way...whether or not you're having intimate contacts, M... helps you get to know your own body. It helps you figure out what turns you on, what feels good and where you're sensitive. Once you know your own body well, you can tell or show your partner what you like best (extracts from sexualityandU.ca).

Most people's first experience with sexual pleasure is through M.... There are many feelings and opinions about "getting off" through M... (sometimes referred to as solo sex).
Humans can become sexually aroused and reach pleasure without partners, and at any age. "Plesure" without a partner may occur involuntarily while the person is asleep, or it may be brought about voluntarily. M... refers to the second type - any deliberate bodily self-stimulation that produces a sexual response.
Self-stimulation is also known as autoerotic or solitary sexual behavior. Besides M..., self-stimulation includes erotic fantasy and nocturnal emissions (also called wet dreams), with erotic fantasy being the most common.

What positive functions do fantasies fulfill in an adolescent's erotic life?

•        They are a source of pleasurable sexual arousal.
•        They act as a substitute for the satisfaction of unattainable or inappropriate sexual  needs or goals.
•        They provide an opportunity for adolescents to recognize their sexual needs and preferences, and to rehearse these in a way that is non- threatening.

What negative effects can fantasies have on an adolescent's erotic life?

They can provoke anxieties and guilt about sexual feelings, which may be perceived as perverted or forbidden.

What do we know about boys' wet dreams or nocturnal emissions?

Although wet dreams are involuntary, they can cause a great deal of embarrassment, and even guilt, in the morning. It's important to remember, however, that nocturnal emissions are a normal and healthy part of adolescence.

What are the facts about M...?

M... is tension-relieving and enjoyable, and does not cause physical harm.
Many cultures accept it as a normal part of sexuality, although some do not.
M... is the most common source of "pleasure" for both males and females, and for two out of three boys, the source of their first ejaculation. Girls seem to start M... earlier than boys, but are less likely to admit to it.

Is it normal to do it?

Yes. Many people do -- but it is also normal not to do it. Children frequently do it and should be encouraged to do it privately (extracts from Palo Alto Medical Foundation).

Top 10 Fact Sheet on M...

	It is not evil, dirty or harmful - it will not make you go blind, drive you insane, turn you in to a pervert, stunt your growth, give you an STD, make you sterile or get you pregnant.
	Both guys and girls do it and it is a normal and healthy part of sexual development.
	It is a very personal thing and should not be done in public places or around people who are not willing partners.
	You are normal if you do it, normal if you wonder about it but don't do it, and normal if you never give it a second thought and don't do it - it is one of the few things in life that is "normal if you do and normal if you don't".
	It may make sexual relations more enjoyable because you will already know what it takes to "please you".
	It alleviates stress and releases endorphins (the pleasure hormones) in to your system making you more relaxed.
	M... as exploration of the body is common in children between the ages of 3 and 6, in teens it becomes more sophisticated and sexually motivated.
	Surveys have shown that 80% of males and 59% of females already did it by age 18.
	Many experts believe that it is more prevalent in the teen years due to a strong fluctuation of hormones; M... alleviates the strain of this build up and is a necessary part of development.
	The only real problems that come with M... are psychological and are the result of unhealthy or weary attitudes toward doing it (if you do it but are ashamed) or abnormal practices (for example, if you do it in public).                       (extracts from About.com)