Which version of Poser? P5 you could do it with dynamic clothing. P4 or ProPak you could try something with scaling and magnets. For an animation, you'd likely need to spawn morph targets from the magnet deformations. (See links to "Poser Back Room" and the links to "tutorials" on the page above for info on these techniques) Or you could create a suitable form using the above methods, or in an external modeling program, and then set it up as a character in the setup room (PPak and P5 only). I think I saw some marvelous clothes by Seraphira in the RMP that incorporate "folding" morphs, but I've not seen dragging morphs.