Hey,

Firstly, millions of believers struggle with sexual desire. Sexual desire is mostly emotional and physical and you can't always easily switch it off with thoughts. You will grow to be able to, but, it never really goes away. The body that God has given you is working as it should, and your body is telling you that. It's nothing to be worried or even ashamed of. There is a difference between letting your body do what it needs to, and using imagery in your mind or using porn. Don't use imagery.

The Bible discusses 'defiling the body', but, if you think rationally about it - would God want you to be equally ashamed of feeling hungry or thirsty? Try to detach your feelings from what you will no doubt have to do (as little as possible hopefully). Don't even think about any girl when you do it. That is unacceptable. It's disrespectful, and can lead to reliance on mental images and pervert the natural reason for sex within a relationship - love and babies.

It isn't 'sexual perversion' to just let your body do what it needs to do. It is perversion if you start to take pleasure in it outside of a relationship, and let it control you. If it happens so often that you feel that it is making you feel shame, do it less often. Persecuting your mind at your age should not be happening. Respect your mind and take care of it. You will serve God with it in the future. If you are too young to get married, and don't want to make your life a crazy misery, forgive yourself, but get tougher on yourself with prayer. God is compassionate. He made you. The more you think and worry about these things, the more the evil one is laughing.

I'm not sure who is visiting you at night, but, one single prayer to Jesus before bed time, to protect you whilst you sleep, will stop it. If Satan tempts you, say "the Lord rebuke you" and know that Jesus has (because He definitely does). That is Biblical. Satan's minions will return to you, as they do to us all. Let Jesus rebuke them. They hate it and flee immediately.

If you disagree with anything that I have said, I respect that. I'm trying to help. I've been (and still am sometimes) in your situation and I'm not going to deny it.

I'll pray for you.
God bless, take care.