The practice of dipping into a container of dip with a chip, vegetable, or other item which you have already dipped into the container, thus contaminating the dip with the germs from your mouth. Generally considered ok if you're alone, but rather impolitic and boorish when at a social gathering. This behavior was showcased on the popular sitcom Seinfeld.

Double dipping is also the term used to describe fortunate members of the political, bureaucratic, and professional classes, actually those who are members of all three, and more, who draw pensions and other benefits from all of them. Actually, this would be triple dipping.

In Canada, at least, this is used in a vain attempt to shame such an ostentatious excess of democratic capitalism.