to being "on the rag", I wonder?

heh, don't think so Jackie! The funny thing is I had not realised this colloquialism was at all exceptional, but a quick googlehaul shows only 33 examples of the feminine variant to 145 of the male's tendency to lose their temper ;)

What's more nearly all the hits are UK sites, with an Aussie one thrown in too; what's more more is that most of the references seem to occur in discussions about football (soccer).

I still have no clue as to the phrase's origins, so over to the detectives...