Source: Martha Stewart
Fold a 6-inch length of pipe cleaner in half, and slip it into the middle of the butterfly shape. Pinch the fabric in the middle to give the butterfly a three-dimensional aspect. Twist the pipe cleaner together at the top and bend the ends to create antennae. Place the butterfly over a 6-inch length of pipe cleaner and hook a bobby pin through the pipe cleaner on the back of the butterfly. This same idea can be used to embellish a hair elastic.