Take and fold lengthwise in half twice. Hold both ends and the give it 3to 5 twists so it now looks like a twizzler now ball it up and jam it somewhere as long as its some where tight. It won't tangle cause it already is. When you ready for them just pull them out they will untwist themselves generally.

It doesn't need to be tightly twisted just enough to hold it.

Small cases for them existed. They were small, but big enough to coil the cord in without damaging it. I've used some HTC earphones from an old smartphone. I don't remember the model, but it had flip keyboard. One of the first smartphones. Those earphones are still going strong. They gotta be 15 years old or so. Easy to clean too.

I was doing this for years.