Not how do I, but how can I? Can I use gel color to paint a design directly onto dried color flow?

Hmmm, that's a good question. Moisture can break down color flow, but if you were painting a small amount on there I think you could. I've used edible markers to add details to the pieces before.

I would make sure to use the color very lightly.

And if you have time, why not make a practice piece and see?

It works, used both fine paint brush and toothpick for very fine work!!!!

Good to know!