Admittedly, I don't always have a clue what will appear on the face of a rock when I sit down to paint and decorate it.When adding the dots I have to keep the nozzle of the bottle clear because it can gum up pretty quickly.Keeping a sewing needle close by is important in this process.
The other thing is to watch out for air bubbles, because they will cause the paint to spit.The paint has the consistency of Elmer's glue and has to be "guided" more than "painted". Using tools like toothpicks, q-tips and rubber-tipped brushes are not uncommon to excel at this craft.