Paint the egg with two coats of white acrylic paint. Let dry completely.
If using ready made waterslide decals, lay each one face down on the egg and place a damp washcloth over the backing of the decal. This will only take a minute to do.
Then gently lift off the backing.
If using Lazertran decals, follow the package directions.
Here are a couple of Lazertran projects I’ve done to illustrate how easy and flexible they are to use.
The egg can then be sealed with acrylic paint sealer or a thin coat of decoupage medium.