Persian and Afghan Jews lightly hit each other with scallions during Dayenu to symbolize the slaves being whipped by the Egyptians.


haggadah Section: -- Cup #2 & Dayenu
Source: http://mochajuden.com/?p=4179, http://www.beliefnet.com/Faiths/Judaism/2009/03/Unique-Passover-Traditions.aspx?p=2