Now that I have figures out the mechanism needed to operate the line for Relic's ears I can refine the design. I have used O-Rings to attach the tube and Line to my thumb and forefinger.
It became evident quickly that you want an o-ring only large enough to go to your first knuckle and no farther.
The final test is a go! I will more than likely make a cap for my finger, more like a sewing thimble that would be easier to find inside a paw. But this works and can be refined over time.