I think the problem with some is that they believe that even if you're a child of God and you may stumble that then you are going to hell. By proclaiming masturbation not a sin allows them to get away with this because they know just about everybody does it or has done it. Everybody, even the Spirit filled Christian, the one walking in the light is going to stumble and fall from time to time. Masturbation is a perfect example of the flesh that wars against our spirit and instead of scarying christians that they are going to go to hell each and everytime they sin unless they hurry up and confess it and repent they need to accept the fact that until we move from corruptible bodies to incorruptible bodies we are going to sin. Our God is a good God and He does not and will not kick us when we're down even though I think alot of christians feel it's their job to do so.
The child of God, the born again believer in Christ has victory in his sights to win the ultimate battle. Masturbation is a sin battle we all need to wage war with and it needs to be confessed to God but the real disheartening thing about it is when you have some christians who then deem it necessary to call those who do fail "failures" and that they are going to go to hell.
The best thing a parent can do for their child, especially in this situation, is to let them know that they can make a mistake and not be a mistake. And like jckstraw72 said we need to let them know that they need to let Christ control it, they need to learn, we all need to learn how to let go and give it to God because He's the only way and the only reason why we win our battles with sin in the first place.
Or is there someone here who would like to boast for awhile???