(OK, so now they have Sunday trading, but still...)
Here is my quick 'n' dirty cummerbund - doesn't every girl have hook 'n' eye tape and featherweight boning lying about the house?
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PS this eBay seller is a good source of silk - and the stretch means you don't have to cut it on the bias - yay! I got some black stretch satin before and it is lovely - must make slippage from it forthwith.