To solve the problem of colored pencils being colorfast when washed...
Use Derwent Inktense pencils. They are permanent after color is activated. Pencils can be ordered in sets of 6, 12, 24, 36, 48, 72, and individual pencils (great if you run low on certain colors). Inktense Products list:
http://www.pencils.co.uk/productlist.aspx?mid=718
Activate the color with water if you don't mind bleeding or want a color wash effect.
Activate with clear, aloe vera gel (not lotion) to prevent bleeding.
I haven't experimented with length of time between drying and washing to remove excess dyes and gel.
Read this Derwent website about using pencils on fabric with fabric medium...dry 24 hours and then heat set.
http://www.pencils.co.uk/files/uploa...rature/671.pdf
You may need to wash and dry and then continue coloring if there is too much gel build-up and color doesn't seem to be penetrating the fabric.