Thanks to all for the ideas..... Chalk... that's interesting!Sidewalk Chalk (I use crayola) is fantastic but also doesn't always wash out right away though it doesn't stay as long as the manic panic.
Crayola Washable markers, LOVE 'EM !! If your dog's hair is reasonably short they are super easy to use. Basicly the equal to the blow pen. I reccently used them for the first time for Jazz's red,white,blue look for memorial day. I rinsed her with water today and a little shampoo on the colored areas and everything done with markers came right out no problems. Of course the red blow pen in the ears hung around and for some reason not all the blue on the tail came off, but again everything done with the markers came off super easy.