Now rub the bag vigorously on some furry cloth or a cuddly toy or fleecy scarf etc. to charge it up with static electricity. This might take a few attempts to find the best type of cloth to create the most static.
Hold the bag up in one hand and you may see the punchings stuck to the sides at various places and some may be stuck together. Try bringing your other hand near to the bag and see what happens to the punchings. After a little practice you can cause them to jump about as if they were alive, leaping from one side of the bag to the other and from bottom to top just like flea acrobats in a flea circus.
Try rubbing a ruler on some furry cloth and bring that near the bag. What else could you try?
After a while you will have to charge up the bag again by rubbing it. If you try this or make up your own experiments let us know what happens.