Aruch HaShulchan 167:31 and Be'er Hataiv 167:22 both say that it is forbidden to throw the (Challah) bread. I have heard that there are some people (I heard that there are some Rabannim who do so) that have a Minhag to throw the bread when passing it around Friday night. Is there a source for this Minhag? What is the reason? How does it circumvent the problem of throwing bread?
I was told orally that the Noda Bihudah, if I recall correctly, defends those who have such a practice as we seek to make our tables similar to the Mizbeach, and the meat that was to be placed on the fire on the Mizbeach (altar) in the Temple was thrown (past a gap between the ramp and Mizbeach).