They also happen to be the cookie that I am most often asked to create a tutorial for.
Flood the outer rim of your cookie with the same color as your outline,
IMMEDIATELY (seriously, don't get up and change the channel)
flood with your next color.
I like this ring to be slightly thicker than the first.
You will make the same motion for each point,
wiping off your toothpick between swipes.
Then, starting at the edge of your cookie,
drag your toothpick between the points into the center.
(keep wiping off that toothpick)
Don't forget to come up from the bottom too!
Let it dry!