Tightening

So I’ve read and been told that when you’re having contractions that your belly will “tighten.” So my questions is, is this like a legit tightening you can look down at your stomach and see? Or does it just FEEL like something is tightening or being squeezed in there?

Ftm and never had a single contraction (not even BH) at all so I really don’t know what I’m looking for.