My little one (3yrs old) wants to put a little color in their hair. Streaks of color. Silly fun. I'm looking for something that's safe for kids of that age, easy to apply, and washes out easily without creating a painful situation or an horrific mess. My googlin' has led me to something called Hair Chalk. Is this the direction to go? Any recommendations? Pitfalls? Is this just an awful idea? Thx!