Autonomy as Freedom--Kant

Before I unfold the story, I had to explain something about me. I start this bad habit 5yrs ago, but since the beginning I have been trying hard to quit this. Keep trying, also, keep losing every several months, and the best record is 230days or so. I have to admit that here is still a long way to go for me. Im a student in college majoring in philosophy. And Kant's philosophy had really given me some inspiration. im not a native English speaker. But i will try to explain, why fap does damage to our freedom.
The only difference between human andbanimals is not we r smarter, but we have freedom. That means, you have the rights to make your own choice, no matter the choice is right or wrong, you can say no, although you have to be responsible for your choice. And think about that, there is a kid, whatever you teach him to do something, he always say no and never listen to you. So you call him a bad kid. But no matter how bad he is, he is better than a dog, cuz he has his own will, he has freedom, he can say no. A dog won't do this, an animal always listen to his natural desire.(sex desire included) The highest stage of freedom is autonomy. That is to say, you r the causes, u r not the result of the something out of humanity(opposite your natural desire). It goes like this, when you want to fap, we all know that's kind of natural desire. If you choose to listen to that desire, that's a damage to your humanity. You are the result of the outside world, you lose your freedom. but if you say no, well, you are the causes. That is why he said, autonomy as freedom.