In the popular song Hey Ya!, Andre 3000 advises listeners to "shake it like a Polaroid picture". This is in reference to the motion that many photographers use when developing film from Polaroid instant cameras. The line actually caused such a revitalization of Polaroid's lagging sales that they sponsored Outkast's tour.
This shaking or waving motion was used in the early days of instant film. The film was a pull-apart film that needed to dry before being handled, and the shaking or waving motion helped to speed up that process. Currently, the most common types of Polaroid films are enclosed in a plastic film, and the image never touches the outside air.
This motion does little to speed up the development of the film, and furthermore, if used excessively, can actually damage your pictures. It could cause the film color layers to separate prematurely or create discolored portions in your photo.
If, by force of habit, you shake your pictures anyway you probably don't have much to worry about--as long as you don't shake too hard.
The ideal way to developed a Polaroid picture is to lay it on a flat surface and keep it away from wind. Do not bend, twist, set on fire, or otherwise disturb the development.
I guess it is best that Andre-3000 didn't heed the advice of Polaroid, or women everywhere would be "laying flat like a polaroid picture".
As an example of the pervasiveness of this line, Wesley Clark was was quoted in Time Magazine saying, "I don't know much about hip-hop, but Outkast can make me shake it like a Polaroid picture."1
A Reuters article mentioned some of the Polaroid info.
1. Thanks to Lord of Nothings for the quote.