I think the biggest problem people have when drawing with crayons is that they regress to being five years old again. They hold the crayon like they're coloring again, instead of applying it like a fine art medium. Another problem is that many people want to make it perform like colored pencils. While similar in application, they are quite different. You should not use crayons and expect them to behave like colored pencils. You'll be setting yourself up for disappointment.
How to Crayon Tint. To crayon tint, your embroidery, start by transferring your design to the fabric. I recommend using a finely sharpened regular pencil, as it won't require water or be affected by ironing. Place the fabric in an embroidery hoop so the back of the fabric can press against a flat surface and color the design as desired.