how to fight addiction

Hi, i am Tony Chan. Just turned 18 about 2 weeks ago. So i guess i am an adult now. Ever since i turned 18, this mysterious lust keeps coming randomly, makes me want to masturbate. I know pornography is immoral, and it has so many other consequences, I really want to fight it. But when lust comes, it is so hard to fight, i always give in. I heard about you guys on Youtube, so i am trying my luck if you guys can help me.
Please help me fight this addiction. Thanks!!
-Tony