"My nickname is Spitting-Fire... you don't wanna know how I got it."

That's what Spitfire whispered to Rainbow Dash after the Wonderbolts revealed their nicknames to her. Now, she's got her curious... how did she earn that nickname? And what exactly does it mean?

(SPOILERS FOR THE NEW EPISODE OF SEASON SIX, NEWBIE DASH. WATCH IT FIRST, THEN COME BACK. Thank you for your time.)