Step 1: You'll need these.
now let's come back for the materials.
1) A ball point pen, should be unified in shape and the tube should be hollow if all parts is removed.
2) A flexible rubber elastic band. Should be thin but strong.
3) Two stapler pins. one is used here. second one is for the time when first one wears out.
4) A duct tape.
Step 2: Making the Slingy
Then place an edge of the elastic band with tape on the side of a pen. Now it is half done.
Make the stapler pin in the shape of the letter ''z''. Place one edge on the hole inside the dart and another hooked up with the elastic band. note: never use the tape at the pin's side. And you have made it.