This issue strikes me as one where the church takes up a position first and finds scripture to back it up later which, of course, is a wholly unspiritual way to approach doctrine. Most Christian sects have gone way out of their way to invent scriptural support for their presupposition that masturbation is a sin. Whether it is a sin or not is a determination you, as an individual, must make (Phil 2:12). Most of us are far too socialized to think of it as evil and taboo to overcome or contest the Church's statutory characterization of the activity, a characterization most people could not immediately identify the origin of because there is absolutely no scriptural instruction regarding this practice.
If she mentioned it at all, your mother may have told you you'd
go blind. She may have said you'd hurt yourself, or break something down
there. More than likely, though, she simply never talked about
it. And you never talked about it. And your friends, probably,
didn't talk about it in other than the most nervously humorous
and unspecific terms. And so you've grown up with this little
secret, perhaps something you've grown to believe is a dirty
little secret, but a secret nonetheless: perhaps the most
personal bit of business any man or woman has. Most people will
discuss their politics, religion, and finances before they'll
discuss their sex life. And they'll discuss their sex life in
intricate and stultifying detail long before they'll ever
discuss their solo sex life, or, frankly, admit they even have
Nothing brings a conversation to a close faster than the subject of masturbation. Most people have a hard time even saying the word “masturbation” out loud, especially in mixed company. I suppose it's like talking about going to the bathroom, but even that is easier for most people to productively discuss than the issue of The M Word. In a world where sex is used to sell virtually everything, masturbation is used to sell absolutely nothing. Where television is inundated by couples of varying marital status engaging in on-screen coitus, masturbation, a much safer alternative to intercourse, is still too taboo to make the airwaves, and arrives on film only in the context of baked goods.
All kids see is people having sex, talking about sex, thinking about sex, dressing sexy so maybe they can have sex, wanting sex, needing sex, warned about sex, protect yourself to have sex, consequences of sex, sex, sex, sex. Not one word about masturbation. Nobody ever got pregnant masturbating. You don't need fresh breath or the latest Sean John couture to masturbate. You don't even have to comb your hair. You never have to buy yourself dinner, or listen to yourself whine endlessly about things you're not interested in. I suppose you could, conceivably, catch an STD by masturbating, but you'd really have to work at it.
In the moral arena, masturbation exists in a gray area, while there are specific rules governing sex. The most commonly accepted moral law of sex is it belongs solely within the bond of marriage. So, to put on my ecumenical collar for a brief paragraph, kids are being inundated, twenty-four hours a day, with images and sounds and over-the-top stimuli that appeals directly to their already over-active hormones, driving them towards conduct God (and certainly the Church) condemns as sinful outside of marriage. Or, barring that, to at least buy a Sprite.
As a minister and a primate, I consider most advertising aimed at youth to be patently evil, as it preys on nascent insecurity issues and creates a wholly invented world adolescents are conditioned to feel they must buy into, emphasis on the word “buy.” Sex is an extremely big part of that world. Sex is more productive to sell than masturbation because sex regards social interaction and contact, and you'll need a new pair of jeans for that. You don't need new jeans to masturbate. You don't need friends to masturbate. Everything Madison Avenue wants to tell you about yourself works against independent thought and independent action. It is in the best interest of evil, greedy commerce to find common ground with the Church and keep the whole issue of onanism, or self-love, securely hidden from the arena of social intercourse.