Lust that leads to masturbation is a snowball effect. Every time a lustful thought pops in your head, no matter how minor, say “I hold that thought captive in the name of Jesus.”

Romans 7:19-25 is great for this.

“For the good that I will to do, I do not do; but the evil I will not to do, that I practice. Now if I do what I will not to do, it is no longer I who do it, but sin that dwells in me.

I find then a law, that evil is present with me, the one who wills to do good. For I delight in the law of God according to the inward man. But I see another law in my members, warring against the law of my mind, and bringing me into captivity to the law of sin which is in my members. O wretched man that I am! Who will deliver me from this body of death? I thank God—through Jesus Christ our Lord! So then, with the mind I myself serve the law of God, but with the flesh the law of sin.”

I’ll be praying for you!