I made this specifically because my brother wanted something that wasn't easily molded with an injection molding machine. The undercuts on the bollards and the jack port should make it impossible, if not unrealistically expensive to make that way.
The picture is pretty self explanatory. Put earbuds in, wind and then push the jack end into the hole provided.
EDIT: This only seems to work with the new iPod / iphone earbuds with the volume control buttons on the cord. Thanks to all those who tried with other earbuds.