What Kai is talking about will work, but you can also do the same in AE natively...
I'm not sure if it will give you the same look that you want, but it's worth a shot.
Using your pen tool create a new path that your ribbon will follow...
Place a stroke on the path (3 - 5 px should do it)
Using Time / Echo to make it flow a bit better
Animate the First Margin from start to finish to yield the results that you want.
Note that you'll have to dump the first few frames while the echo loads up....