This is obtainable in practice mode if you set instinct to infinite.
Activate Kim-Wu's instinct mode and you will generate one dragon every few seconds, to a maximum of three. Push

or

and

, depending on your preferred style to fire a dragon. Do this five times and the achievement is yours.
To clarify, the above icon means push Up on the right stick, not press it.
If you want to get this outside of practice mode, you have a few ways to gain dragons. These are:
Landing a Dragon Counter (

/

/

)
Landing a Firecracker Ender (


+

/

/

)
Activating Instinct