I quilt for others and use the blue water soluble markers for lights(or the purple air erasable) and a Chaco chalk pen or the Fons & Porter ceramic pen(finer line) for the darks. I do sometimes need to use a stencil and loose chalk--I have a pounce pad as some stencils are made so you have to use them (have a net in the spaces) but mostly I use a sponge paintbrush to "paint" on my chalk on the stencil. To keep it from bouncing off, I give it a light coat of cheap (like Aquanet) hair spray. But even then you will find that much handling of the quilt in the quilt process will rub the chalk off. (I never use colored chalk as had a problem with the yellow). Some use UltraClean Washable Crayola Markers but I had a bad experience with them when the customer had starched the fabric and it seems to have set the green marker. I haven't used it, but some say a "sharpened" piece of regular bath soap will work well too.