"Tickling the Ivories" is an American term, likely from the 20th century, that refers to playing the piano. The white keys of a piano were covered with a veneer of ivory, which is no longer done. In this image of a 1930 vintage Steinway upright, the keys are worn such that you can tell it's been played (or "tickled") quite a bit over its long lifetime.
f/22, 1/4 sec, ISO 1000, EC -2.67
Photo taken January 2013
Uploaded on 1/15/2013 4:36:35 PM
Made with Canon EOS 5D Mark III Digital SLR Camera