Step 4: Prepare your Styrofoam or Cardboard Holder
Prepare your Styrofoam or cardboard holder. I had this handy cardboard packing from my husband's drum set that worked out well for this project. I just made holes in the top layer, then took it off and laid it on the second and marked where the holes would be so it lined up. Then I made the holes in the second layer. I used a pen to make and mark the holes. Use a pen you don't care about and is pretty normal (no fancy pens here) and sturdy, though mine still worked when I was done.
Then I took one of my cookie sticks and used it to make sure they would go all the way through the top hole and at least partially into the second. They will be heavy, brownies are dense already, and you want them to stay standing and not hit each other.
If you are using Styrofoam, use the cookie sticks to start the holes. The sticks are fatter so they probably won't just go in the styrofoam and you don't want to be struggling with it later when you have a heavy, wet brownie pop to deal with.