The Jews in Egypt had a peculiar local custom. Each participant would sling the napkin containing the matzah over their right shoulder. Then the leader of the seder would ask them "Where are you from?", and they would answer "Mitzrayim -- Egypt". The leader would then ask again, "And where are you going?". They would then sling the napkin of matzah over their left shoulder and answer: "Yerushalayim -- Jerusalem!".

In some families, the leader would take the seder tray and go around chanting and lightly banging the tray over each of the participant's heads! Some say this is to place each person under the "protection" symbolized by the seder plate. Each person was "passed over", as it were!

haggadah Section: Maggid - Beginning
Source: Dr Maurice M. Mizrahi, Fort Belvoir Congregation, Virginia