Food colour pens now come in a variety of colours and options. All pens have edible ink so are fine for using on edible decorations. We have pens which look like a normal ‘felt tip’ design with a finer nib on the other end of the pen, we also have refillable edible ink pens which are also dual sides with one being a fine brush and the other a pen type nib. We usually advise that you have a good contrast if you are going to directly write and/or draw onto the sugar paste/fondant. It is also, where possible, a good idea to allow the surface of the cake icing/fondant to dry this makes it easier to use the pen with less dragging and less ‘bleeding’.