Combine dry ingredients (flour and oats) in a medium sized bowl.
Add water and food coloring if using.
Stir until mixture is no longer wet, if it seems sticky add a little flour. Sections or clumps may form this is fine they with come together when you knead the dough.
Flour your counter or table and turn the dough out onto the floured surface.
Knead dough for 3-4 minutes, the flour on your surface should help with any more stickiness. Try not to over flour or it with get dry and crumbly.
When done playing store in airtight container for 1-3 days.
Have fun playing with the little ones in your life. They are only little for a little while.