F16 or other, finger sling

I read the F16 thread with interest because that's what I'm shooting at the moment.

Someone mentioned using a finger sling instead of a wrist lanyard. I never shoot without a lanyard after a scary near miss years ago.

But I never heard of the finger lanyard approach. Can someone explain how to make and use these? Are they just for safety or do they also stabilize like the wrist one does?

Thanks