It's ancient Blondish word, coming from a famous myth in which the tribe were suffering from malnutrition after years of blighted crops from their dietary staple, the forests of ice-cream trees, around whose tending the rituals of tribal life were built.
After consulting the entrails of various game-birds, it was clear that the blight was due to a curse from the constellation Taurus. Rather than offer sacrifices to appease Taurus, the warlike Blondish tribe tried another tactic more suited to their strengths.
One of their number, a fearless warrior princess named Harriet, laid a feast of ice-cream and other delectables that had been newly landed at The Wharf that day, fresh from the land of the White Rose. With this irresistible bait, she lured Taurus down to earth. Once the bull had come down and was tucking in gluttonously, Harriet then trapped it in her big hunting net.
Taurus was furious. He thrashed, and bellowed, and foamed at the mouth, and threatened, and demanded to be set free. But Harriet would only let him go free if he promised to make sure that the ice-cream forest bore fruit (and vanilla, and chocolate) for evermore. Taurus was a proud bull and he wouldn't be held to ransom like this by a human, but eventually he complained so loudly that he woke up all the other constellations. They forced him to do as Harriet asked, and Harriet in turn agreed to let him go free.
It took a long time to set Taurus free. He'd got his legs and horns all tangled up in the net, and had cut himself on some of the sharp edges of the knots on the sides of the net. By the time Harriet had set him free, the net was covered in blood and needed a good wash.
However hard Harriet's team of domestic slaves washed the net, the blood wouldn't come out. As the years went by, Harriet became more and more famous amongst the Blondies, and they began to call her “Siduhe”, meaning “Fearsome warrior Queen of the Red Bag”.
Considering that blondness is a recessive gene, and the fact that we live in communities of mixed hair colour these days, it's no surprise that the word Siduhe has passed out of common circulation. However, traces of the myth live on in the phrase “Like a red bag to a bull”.
Plenty of work thanks Jon, but today's stuff is the sort of stuff where I'm lucky enough to get to alternate periods of frantic Henny-Pennying with periods of waiting aimlessly for someone immensely important to finish saving the universe before they can attend to my modest requests.