Use a toothpick to pick up the colouring from inside the bottle or pour a small amount in a separate bowl. Swirl the colouring around your frosting. To get the right hue, add the colouring gradually. Add drops of colour slowly to agar agar, jelly dishes or even drinks too. Knead into fondant, dough or even play dough. A tip is to drop a few drops of colour into a small amount of water and mix evenly before adding this colouring to the fondant or dough for a more even distribution of colour without too much kneading. It can also be used to make any dish look more vibrant.