Widened state of lips. Workers are obliged to use it because callers can hear the form of the mouth. In case of non-compliance you are threatened with one-to-one-meetings with slimy smiling team leaders and wage-cuts.
The song "Smiling" appears on the album titled The Beta Band and is track number eight. The song also has a video on the The Best of the Beta Band where the band are in Scotland doing spontaneous things.