This is a messy craft so you will need to Cover work area with something like a plastic tarp (so things don’t stick to it) or large plastic bags.

Blow up balloons to the size you want your finished egg decoration to be.

Multi colored string looks great as well as plain colored string depending on the effect you want .

Now Put the colored crochet string in a plastic bag and put stiffener or wood glue in it with a bit of water to dilute and make it easier to work with. Make sure string is well covered.

Pull string out a bit at a time from the bag, using your fingers to squeeze excess stiffener off. Wrap around the balloon in a criss cross fashion. Until it is well covered.
The idea is not to make it solid so allow small gaps in between the layers of thread .

Allow to dry
When egg is dry pop the balloon and remove it carefully.
Then you can glue ribbons, pearls, laces, or other decorations on the outside..
Or
cut it open and fill with Easter grass and other decorations then glue the seam back together with wood glue. Or you can just hang it or put it on the table as is.