This is fun! At first, I was worried about messing up the "puckers", but instead, this technique makes the beads even rounder! That's because the footprint will spread out along the mandrel a little more or a lot, depending on how much heat you are applying.
Make your base bead, apply dots, stringer, frit, basically anything you want, and melt in, and round out and shape your bead. (shaping is important to ensure that your bead holes will still be nice when you're done with the swirl) This shape that you're trying to get depends on what you want your end result to be: either a round bead, or a football/lemon shape for lentils, squeezed, cubes, tabs, etc.
Then you are ready to get mean
Overheat and let your bead start to droop, then start turning the mandrel away from you (really, you have to think you're doing this to keep it from dripping off of the mandrel, lol!) and keep turning. As you turn, you can pause a few times to let it droop some more, but then keep on turning until you see the swirls you want.
Now you can leave them round, or press, mash, squish, whatever you desire! Something I found out about the dreaded bubbly pitting frit Copper Blue! - It will eventually stop the horrors if you work with it like this, and will turn out smooth and glassy! Just still be careful about not applying too much heat when you do the final shaping up.