I personally have this weird thing where I only color in my wolves. My humans are shaded with a pencil. I don't used colored pencil to color or crayons markers. I use Copics. They are a type of marker that you can blend, and shade with (yes, a pen.) But they are VERY expensive... What do you you use?
My original designs and everything! Please, they are not free to use. The upper right human sorta reminds me of @SmilingSnowflakes Haha.