[1][2][3][4][5][6] Stamping is usually done in response to seeing a specific subject, such as a white horse or mule.
[2] The motion of striking the palm with a closed fist after it has been wet by the thumb is also suggestive of an exaggerated imitation of the action of using a seal.
These superstitions suggest that one must stamp one hundred or a similarly high number of the subject in question to bring themselves luck, prevent bad luck, or make a wish come true.
[3][5] Another superstition suggests that stamping the first robin one sees in the springtime will bring the stamper good luck.
[6] Race-based stamping appears to be more common in the Southern United States.