In days of old, I know nuts, not candies, were thrown, but who threw them? Men, women or both?
Nowadays, the shteeble custom is for men to aggressively hurl hard candies, aiming for the head. Was the nut throwing custom like this, or was it a gentler affair?
And what about the singing? When I was young, no song accompanied the pelting. The bags rained down in silence, Now, there are at least two traditional tunes, and if no song is sung, you can expect the old men to hum.
When I was a kid, we used white bags for grooms, and brown bags for bar mitzvah boys. Now, you hardly ever see paper bags anymore. Instead, they are usually made from some kind of mesh or satin, and mothers who love their sons are careful to pack them with soft treats, only.
So far no official rules governing this tradition have been published, but how long can that last? I expect when a new code of Jewish law is written (and don't we get one every few generations?) a chapter on this practice, upgraded to ritual, will be included.