I've read many tutorial about smudging and there's somewhere I'm always stuck at. In this tut :

http://forums.d2jsp.org/topic.php?t=3189295&p=16295887#p16295887

It says the apply "Filter>Sharpen>Sharpen so that the brush gets a "broken-up" effect, but all it does for me is making the brush lines clearer, like it would do when sharpenning an image to make the face clearer.

What am I doing wrong?