The smear ensures a controlled quantity and even depth of your chosen topping across the surface of the Pringle. Achieving a satisfactory smear is a simple matter:
Cover the end of a table knife with your chosen topping, ensuring that the knife
picks up a healthy scoop. Then draw the blade across the surface of the Pringle,
sweeping towards yourself. Be careful not to damage the Pringle: they are brittle.
Gentle support with fingers and thumb around the edge of the Pringle should provide
sufficient support. This picture illustrates the application of cream cheese in
the early stages of a New Yorker.