I'll add, one time I decided after making enough batches of standard recipe MMF I would do some experimenting. I tried adding various amounts of oils, corn syrup, shortening, extracts, water and dabbled in using less PS. I decided to do this simply because my fondant turns out really hard to knead and hurts my shoulders! LOL I figured there HAD to be an easier way!
-Well, I found that adding a few teaspoons of an oil (canola, vegetable etc) helped immensely with pliability and moisture but prevented it from hardening nearly as fast with regards to decorations.
-I found adding less PS than normal eventually caused the fondant to droop when you pick it up after rolling, and also caused the fondant to have the tiny air bubbles and larger air bubbles in it once applied to the cake. It also caused elephant skin.
-The corn syrup made it more pliable as well until I got to experimenting with more than 2 tbsp. That made it more sticky, I think.
The best finish was achieved when I added a small amount of oil and a small amount of corn syrup. The little air bubbles are from not having enough PS, and it drooping can be attributed to the same. I know this is a repeat of info, but something told me it wouldn't hurt to share anyway!