Get a piece of cord or string (not too thin - don't want any finger amputations!!) and tie it into a loop. The cord below is approx 28" long.
Turn one end back to make a double loop:
Fold it over to make a kind of noose:
Repeat on the other end and slip your fingers into the nooses - et. voila! A finger sling!
This is easier than it sounds, and it's quite secure... some people use these as permanent finger slings.