Is folding with a spatula really necessary?
The mechanism of a whisk is very different from a spatula. One is able to very gently fold the ingredients with a spatula while minimizing mixing. A whisk's tines will cause much more damage to the whipped mixture, deflating the fragile bubbles you worked so hard to create. It's really worth practicing with the correct tool. It won't take you long to master this. 

Simply cut through the ingredients with the spatula and lift about 1/3 of the mix from the bottom and gently fold over the top, then turn the bowl and repeat. Fold as little as possible to just combine the ingredients. In some recipes complete mixing is not even necessary.