Though there is no formality in friendship and they are very frank with each other, you may maintain this frankness but consider your friends as your brothers. You may like to read some good quotes about friendship to be wiser about the subject. This is because wise and famous people have said a lot about friends from which you can learn a good lesson.
If you treat your friends as your brothers then the amount of love also increases manifold. It is but natural that family members are always given priority over outsiders. Therefore if your relation with your friends is like a brother then they will surely get the importance they deserve.
This does not mean that you keep your friends in your house without the permission of your parents but the point to highlight is that your treatment and attitude towards your friends should be brotherly and extremely good.