lovingmama

The best thing that worked for me are fabric markers. They are not that expensive.

I use freezerpaper on the backside of the fabric, to make it a little bit more sturdy.

The children love it and it is amazing, when you put the squares together for the quilt. Wonderful memories!

nycquilter

I put freezer paper on the back for stabilizing the fabric while the kids draw. I've used fabric markers, Crayola crayons (other brands are not as good), and gelly roll pens, which come in a ton of colors.

just_the_scraps_m'am

if you use the search feature at the top of this page, and search crayons, there are quite a lot of threads with info to help you!