One of the ceremonies at the rehearsal dinner involved a sheet dividing
Sam and Allyson, each of whom
held a handful of rice (?). At the signal of the Zoroastrian
priest (?), the sheet was dropped and Sam and
Allyson pelted each other with the rice. The first to hit the
other would have the power in the relationship.
As you can see, Allyson may have had a little help with the timing.