Laying His Finger Aside of His Nose... Collage Sheet

That was always a phrase I wondered about, and here's some good info from a recent internet gem, A Visit from St. Nicholas: Annotated:

"Laying his finger aside of his nose" was a gesture that would have been understood by the original audience of the poem. This expression has come to famously be associated with the legendary figure of St. Nicholas, or the contemporary Santa Claus. According to Stephen Nissenbaum, the sign "represented the equivalent of a secret wink - a visual way of saying something like 'Shh! I'm only kidding' or 'Let's keep it between the two of us'".