Anyone have any suggestions on how to do this technique?
Look up the UK decorator Paul Bradford. He does all sorts of fancy stuff with chocolate and offers tutorials for sale.
I'd suggest using modelling chocolate put through a pasta maker. It's still malleable enough afterwards to fold into pleats
i would roll out/trim the modeling choco then insert dowel to make the pleats and apply it to the cake -- i'd work on my marble top so i can control the heat -- you want it warmer (more flexible) to roll out and slide in the dowel then cooler (firmer) to pick it up and apply it -- marble helps w/that -- then you can just use (the heat from) your finger to smooth over any cut edges -- might knead in a tad of fondant -- maybe maybe not