Does this sound okay:?

In the first sentence, she might be squeezing his chin a moment after she speaks. The timing is a little indefinite.

In the second one, the action and the conversation are simultaneous.

The comma rule used regarding “as she squeezed his chin” is this:

Use a comma before a coordinating conjunction that separates two independent clauses.

“AS” functions as the coordinating conjunction here, so you do have a reason to add the comma.

People who recently graduated may have learned the pathetic journalistic grammatical rules perpetuated by newspaper editors.

If you’re going to use the second one take out the comma between “mother” and “as”.

Remember, ‘mothers’ show their love openly. How the ‘act’ of showing it matters most, not so much the ‘form’ meaning exactly the same thing.

Just picture it in your mind.