Bro what you need to do is to discipline you body and engage yourself in serious prayer and fasting and when that strong irresistible urge comes, without delay go to your room in your privacy, go on your knees and pray seriously and while praying use a cane, belt or any wiping tool and scourge you body seriously. It will help tame your flesh because d body hate pain and it can do anything to avoid it and when ever the thought comes again remind yourself of pain you felt during d previous wiping of your body it will help calm your body down. And never give up, keep fighting and take seriously this instructions you will overcome by God's grace