The things you'll need
donut shapped cereal (like cheerios, fruit loops etc.)
Capri sun straw (or equivalent)
Step 1: The Straw!
Start with the straw. The cool thing with the straw is you let the kiddos drink a Capri sun as part of it so it gets them involved early.
Next wet the tip of the yarn.
Place the yarn in the blunt end of the straw.
Next suck the yarn through the straw. (choking hazard) this part takes patience and a willingness to inhale yarn for your children. If you are having trouble you can try twisting the yarn (with the grain) and pushing the yarn.
One it's through tie the yarn in a large enough knot so that it does not easily slip through the straw.
Once the knot is big enough, force it into the straw by pulling it, but just enough to get the know into the straw. If there is excess yarn sticking out the front just cut that yarn off.
Step 2: Start Threading!
It helps to have a pan or plate that they can easily remove the cereal from.
Now the important part. Hope that they are entertained enough to allow you to escape and take care of your holiday chores.
Step 3: Apply to the Holiday Tree
p.s. if you have a feline who is a fan of cereal, your decoration may not survive.