If you feel resistance, you cut the strings loose so that you can continue.
Pull the start of the straight-edge cut piece loose, so that its end becomes fluffy.
Pull the start of the straight-edge cut piece loose, so that its end becomes fluffy.
STRAIGHTENING

Straighten the part you are working with, using a curler, styling tongs or an iron (on the 'wool' setting), until it has a slight wave.