When a women doesn't want to say she is on her period. This is the code word for: I'm on my period, don't mess with me!
Coloring is a perfect noun-that is used when you use this term.
Don't mess with Christy, she is coloring with her red colored pencil today, and being a total BY-otch!
Angela: I don't feel like swimming today, I am coloring with my red-colored pencil until Friday, and NOT in the mood.