The Best of Making Things: A Handbook of Creative Discovery. I think it is a rag rug technique but I have been using it to make ruffles for kids and adults. These also make great tutus if you tie them round the waist.
These are for sale in the Mini Magpie London Shop on Etsy
(I know thrumming sounds smutty but its not, I promise.) (Well i guess it could be if you wanted it to be!)