Elastic Foreskin Tugger

thingiverse

I will update this summary later and include a more detailed photo. But this is designed to work with elastic cord wrapped around one leg and then inserted through the hollow center and knotted or glued to connect it to the Tugger. I would recommend using a form of spring catch or other adjustable knot so that the tension can be adjusted. It's designed in MM and fits quite comfortably with platex wide mouth nipples as the gripper cut to fit.