I always use the "alternative' MMF recipe from this site (marshmallows, sugar, almond flavor and 1/3 c crisco) and I have trouble with it "pitting" once it's on the cake. It develops little tiny divots and isn't smooth, only happens in some places on the cake, not necessarily at folds. It's only a problem when I want to paint it, the paint sits in the divots and makes it uneven. Anyone had this problem or know what's wrong? I roll out on a Wilton fondant sheet using more powdered sugar. I generally make the fondant several days in advance. Thanks!
Make sure that you've kneaded it until it's soft before you roll it out. Then roll it out with cornstarch instead of powdered sugar. When you've got the piece rolled out to the size that you need, rub your hands over it until it's silky smooth, before you pick it up and put it over the cake. Don't flip it over the cake, make sure your pretty top side ends up the side that shows on the cake too.
Oh and you might find it easier to roll out on a piece of thick clear vinyl...you can put the wilton mat underneath for the measurements, but nothing sticks to vinyl, it works even better than silicone in my experience.