What is "unzipping"

Usage examples of "unzipping".

Inch by inch, the blouse parted and she slipped it off, dropping it to the floor before kicking aside her shoes and unzipping the pants.

As he turned to follow he saw, with horror, the bolts along the central spine of the ladder begin to burst, unzipping like a jacket.

I heard Crying, the spokings and unzippings of grief, when the breath sounds as thick as fluid, the weeper gagging on her pillow suicide.