Get an Exceed
Use your Exceed to fly right above a dragon's head.
Note - The dragon needs to be attuned to your own element.
Let the Exceed drop you on top of the dragon's head.
Proceed to eating the dragon.
Note - during this time, the dragon will thrash about to knock you off. Hold on for dear life.
Continue eating the dragon until the dragon feels an immense power and presence from your small frame.
When the dragon asks what you are, reveal that you are the son/daughter of the dragon king of that elemental power.