This is one of my favorite little do-hickies that I use when pulling elastic through a casing. This bodkin is so much better than the old, time-consuming safety pin method and doesn't come un-done like the tweezer-type of bodkins.
I just thread my elastic through and tie it in a knot (my bodkin is a little bowed from all the use).
Start threading it through the opening in the casing...
Walla! This took about 25 seconds! I love it!
Unfortunately, you still have to do it the old fashioned safety pin way if you are making something with a small opening (like the end of a sleeve or something). But this is definitely a neat thing-a-majig!