So here's our little milk and cookie.
Since the twins are little and love to be in their carriers, we wanted to build their costume around their front packs. We thought of lots of cute easy-to-make combinations (salt and pepper! two peas in a pod! hamburger and french fries!) but ultimately went with milk and cookie. 99% of the credit for the manual labor goes to my amazingly creative sister-in-law, Ellie.
A quick tutorial, in case you're also thinking about a baby carrier costume:
semi-structured front baby carrier (we love these)
heavy duty scissors
fabric in whatever colors the costume requires
colored felt for smaller details
fabric or heavy duty glue
1. Cut out the cardboard in the shapes you want. For the cookie, we did a simple circle, but the milk was a little more complex because we made it 3D and added a straw opening. (The straw is a paper towel tube.)
2. Wrap the fabric around the cardboard and glue to the back.
3. Cut out felt and glue onto fabric to add details to the costume. (This is what our chocolate chips are made of, as well as the stripes on the milk straw and the milk lettering.)
4. Cut 2 or 3 fabric strips (about one inch times 14 inches) and glue the middle of each strip to the back of the costume.
5. Attach the costume to the carrier by threading the fabric through the holes of the carrier and tying the ends of the fabric securely together. We like to tie the fabric knots to the side they're not digging into the baby's back.
The side views (you can see the fabric strips attaching the costume to the carrier, and you can see the 3D milk carton):
candy corn popcorn snack helps too. ;)