In doing a Google search for Worm quilt swap, I found a book titled, "Open a Can of Worms". It had this description:
What is a worm? Author Debbie Caffrey explains it's a strip of fabric that is 2.5 inches wide. Sew dozens of beautiful, scrappy quilts simply & very quickly. Start cutting 2.5 in strips now!
I had never heard of this swap either. We always called it a strip swap.