Childhood question II: origin and extent of the "shame, shame!" gesture?

If a boy showed some kind of preference towards a girl, the rhyme we’d use was:

Shame, shame, double shame,
Now I know your girlfriend’s name!

And the finger action we’d call “slicing the carrot”.

(Saskatchewan, 1980s)

Some more information in these pages. No definite answer. Apparently the origin is unknown. The most authoritative answer seems to be from Desmond Morris, quoted in the first link (which despite the title “Mystery of Origin Solved” does not answer the origin question). He says it’s restricted to North America and the rubbing is “thought to symbolize friction”, which doesn’t make a lot of sense to me. What’s friction got to do with shame?

Hey, I’ve heard of this site before:

–Mark

You’re forgiven because Shame Carrot would make an excellent band name.