What is "the fabric" of space-time?

Take a rubber band and draw 7 dots on it, equally spaced apart. The middle one represents our galaxy while the others represent other galaxies. When you stretch out the rubber band, the dots that are farther from the middle one move farther and faster away from the dots that are closer to the middle one even though the rubber band is stretching by the same amount across all the dots.The distance and speeds are compounded by the space between our galaxy and the nearest one and the distance between the nearest one and the farther ones.Make sense? Yes.

Right.I've seen arguments against the twin paradox that go something like: according to relativity, its all based on your frame of reference. So, to the twin on the spaceship, the earth is moving away at 99% SoL and the twin on earth should be the one that is younger, not the one on the spaceship. But we know that the spaceship is the one moving because it is the one that is experiencing the acceleration.

I didn't watch the video because I'm at work. That'd draw more attenion than me just typing and reading You're more than welcome for the help. I'm just paying it forward anyways and you should do the same.