I guess it depends on what pellets you are using. The pellets I use have 5.55 mm heads and fit tight in the breech. I push (while I twist the pellsat) them the rest of the way in and this flares the skirts.
If you have loose fitting pellets to begin with, you might have to flare them in your hand first but this seems like a waste of time in my opinion. I would just buy tighter fitting pellets to begin with and just load and shoot.