From the source:
 
“Twilight, We would think Our sister would inform us if she were thinking about turning somepony into an alicorn. At the very least she would have the decency to send a letter.”
 
“She didn’t tell you about Cadence,” Rainbow quipped.
 
“I was imprisoned on the moon,” Luna shot back angrily at the cocky pegasus.
 
“She didn’t have the decency to send you letter than either,” Rainbow sniped, chuckling loudly, clearly pleased with her insult as she hovered in the air close to the cobalt alicorn.
 
“Mark my words, Element of Loyalty or naught,” Luna growled as she wheeled on Rainbow Dash. “If thou doth not shut thy hole in the middle of thy face, We shall most assuredly strike thee so soundly in thy skull, the resulting bruise would surely give rise to the insane thought of thou’s own ascension to alicorn!”
 
“I’d like to see you try,” Rainbow taunted, relishing in getting under her skin. “But before you do, make sure you send Celestia a letter. It would be the decent thing to do an all.”
 
“YOU INSUFFERABLE FEATHER DUSTER!”

You know I have the power to manipulate dreams? I hope you enjoy your specially crafted nightmares for the next few nights.

@JP  
Oh, Luna’s sings are soft. Very, very soft. Also warm and silky to the touch^^

@JP  
and everypony else seems extremely shocked about it. AJ and Luna look pretty pissed!

Luna’s wings feel so soft and nice Dash can’t stop touching them.