Why is my fondant cracking?
Just so, why is my fondant not stretchy?
If your fondant does not feel elastic enough even after kneading it well, add up to 1 teaspoon CMC powder, Tylose powder or gum tragacanth to the recipe. If your fondant feels dry and cracks or feels very firm or crumbly, knead in a few teaspoons of melted shortening.
Also to know is, how do you smooth out fondant without a smoother?
Use leftover fondant dough shaped into a ball, dip your hands in cornstarch or use a piece of thick foam to smooth out the fondant on the cake. Roll out prepared fondant 1/4-inch thick. Use cornstarch to dust the work surface while rolling the dough to prevent fondant from sticking.
Before I go on, I should clarify that fondant melts at 35 degrees, so in hot weather fondant may melt and sag off a cake regardless of how well it was prepared.