This brush is single use and can only be used to color one dino. Applied colours are permanent, and will pass on with breeding.
How does it work:

• Equip the brush and hit the dino you want to color
  

• You can select the colors using a nice GUI (a window that shows color options)
  

• You can check out all the colors without applying.
  

• When you are happy with your design, simply click "Apply colors" and it's done.
  

When activating the brush by hitting your dino, you:

• have a certain amount of time (more than enough). If you take too long, the brush is destroyed.
  

• can move around, but if you go too far out the brush is destroyed.
  

For both there are clear alerts and a countdown, to indicate what is going on.