Is Masturbation a sin for Christians?

Matt 5:28-29 "But I tell you that anyone who looks at a woman lustfully has already committed adultery with her in his heart. If your right eye causes you to sin, gouge it out and throw it away. It is better for you to lose one part of your body than for your whole body to be thrown into hell."
For some psychologies said it a human behavior that you cannot control or some says it is a parts of behavior.
As a Christian I believe this because when we considered this thing as a behavioral habit, we constantly create a preparation for a bigger sin
But what if no illicit fantasies are included in masturbation? Is the act then sinful? By scripture, there is nothing to indicate that it is. Specifically, if the act is done merely as a hedge against temptation and as the body requires then there is no need for the above sinful "crutches". This is hardly exciting, and a rote act of keeping the body in submission. It cannot be done often, as the body is not that demanding if left alone by a perverted imagination. On the other hand, if we attempt a pent-up self-sex life, then we find that the body needs help from the soul through illicit fantasies, and then sin is clearly being committed.
I hope this is clear. Were it not for our perverted imaginations and lustful sense of expectation, our bodies would not cause us much trouble. It is our minds and hearts that need "treatment". It is like rev-in an engine near red-line at every traffic signal, and all the time it is running, and then complaining about the eventual engine failure. Sure the thing can rev, but not all the time. It was not made for that.
From Scripture, the line not to be crossed is the line of illicit imagination. And what a line! Minus the sinful fantasies, which are the fuel for most masturbation, all the fun and zest would be taken out of it. Thus, it would no longer be a topic of interest to you or anybody, any more than the act of going to the bathroom. It would be just "doing what was needed" to keep the body from exploding from within.
Sex was not created for this, you can be sure. That God allows masturbation to even work is a mystery (ever try tickling yourself?) and so it is reasonable to assume that it is a "gift" to keep ourselves from temptation.
Eph 5:3 (NIV) But among you there must not be even a hint of sexual immorality, or of any kind of impurity, or of greed, because these are improper for God's holy people.
Much like a person who is an Alcoholic must avoid any kind of drinking like the plague, where others can drink with moderation and without sin, the same principle applies here. So people might come to different conclusions concerning masturbation, and that is anticipated within our faith. Each man must live in holiness before the Lord in his/her own body, and this might mean different disciplines and personal leading in each case. What works for me or you... we should not impose on anybody else as a stumbling block.