[Welles]

I use the Forward Warp Tool (the one at the top of the toolbar at the left) and a brush setting fairly small. The brush setting size will depend entirely upon the size of your image. I used a brush diameter approximately 2X the size of a square.

Then small movements should move the lines sort of like the smudge tool only with less smearing. It will take a bunch of small movements to get those lines squiggley.