sentences:  When the icing may crust faster than a design can be filled, the design can be blocked off first into smaller sections.To block off the design, cookie decorators pipe the outline of the cookie as usual, but then section it off in smaller sections, filling them in one at a time.Empty nooks and crannies that the decorating tip didn't pipe into can be filled by carefully dragging a toothpick through the icing into any empty spaces.