Here is a really useful technique referred to as “folding”.
The purpose of folding is usually to introduce a light and airy component (like whipped cream or whipped egg whites) to a heaver, denser component, resulting in a lighter fluffier batter. It’s really a simple technique, but one that has to be done carefully.
The whole point of folding, is to prevent over mixing, and keep the air that is whipped into the egg whites or whipped cream intact, to achieve that light, fluffy batter.
I found this really great video that shows exactly how to do it.
See that wasn’t so hard!