To do this you use soft wax chalk, also called soft pastels.
You can pick up a box of 36 of these chalks from Michaels for $4.99, see them online here.
All you need to do is put a towel around your neck and shoulders(you don't want the color to get on your clothes or skin)
Take a spray bottle and mist the spots you wish to temporarily color with water.
Rub the chalk on the damp pieces of hair. Any color combination or style you want.
Yep. It's that easy!
Hopefully some of you guys like this and try it out. I have naturally blonde hair so it showed up good on me, I heard it works on darker hair colors as well though.
Show me pictures if any of you try it!