Step 1:
Get an Exceed

Step 2:
Use your Exceed to fly right above a dragon's head.
Note - The dragon needs to be attuned to your own element.

Step 3:
Let the Exceed drop you on top of the dragon's head.

Step 4:
Proceed to eating the dragon.
Note - during this time, the dragon will thrash about to knock you off. Hold on for dear life.

Step 5:
Continue eating the dragon until the dragon feels an immense power and presence from your small frame.

Step 6:
When the dragon asks what you are, reveal that you are the son/daughter of the dragon king of that elemental power.

Step 7:
???

Step 8:
Profit!!!