In our household, "Mustards" are cheeks bunched up in a big smile. They are so-called because they first appeared during a viewing of the Father Ted episode "Speed 3", where the appearance of philandering milkman Pat Mustard gave rise to an impressive showing of smiling cheeks. Hence "the Mustard effect", or simply "Mustards". Here my fiancée shows off her Mustards, which are my favourite Mustards in all the world.