How do you make royal icing thick and thin

What you will need to make Royal Icing:

• 2 egg whites
• 500g icing sugar
• 1 tablespoon lemon juice

Instructions:

1. First, you put the egg whites in a bowl and add also the icing sugar until the consistency is and smoothe.
2. Then add the lemon juice. If you want a thicker texture for borders of biscuit, then I would recommend using a bit of lemon juice but If you are doing the technique flooding (where you fill the cookie on top) then I would use more lemon juice.
3. Once the Icing has dried share with friends and enjoy.