From a CR post:
"Soon the jargon evolved. When a cork was popped, power was released, bubbles escaped, the elixir went flat, no more oomph or energy. So, dropping your cork or having no more cork means you're out of it, flat, dead, pooped, no more stuff. Ergo, the racers would hang a cork on their bikes so they'd never be "out" of cork. There would always be one more effort left for a "jam" or sprint. Conversely, if a rider said he "uncorked" a sprint, well, he "jumped," "wound" it up, and took off. Or, if he pulled their corks, he went so hard the opposition got "dropped," shook" off, and had no cork left. They were decimated. HAH! Great Fun!"

EDIT: looks like rhm's link above has the same story.

That link is interesting too! Thanks for the explaination! Don't know if I will put a cork on it or not!

Those Binda Extras can be a b***h to twist and still be able to feed through the slot on the other side. But they're also very thick, which makes them resistant to moving, which is what the twist is intended to prevent.

"The Cool Factor: Welp, pretty much everthing!"