The Princesses of Equestria were second-to-none in many ways, but among those was practical jokes. Things came to a head one day when Luna nearly stepped on a few of her guards after Celestia had shrunk them down. Originally thinking about returning the favour Luna instead decided to throw a curve ball.
 
Twilight, Rainbow and Pinkie were surprised to find themselves swimming in a warm brown liquid but, when they felt movement all around them, they looked up to see Princess Luna’s massive face looking down at them with a slightly apologetic but also rather amused look.
 
“I am aware that this may be terrifying for you,” She whispered, “But rest assured that all three of you will be perfectly safe. Consider it a giggle little adventure.” And with that she brought the cup of tea up to her lips; anticipating the look on Celestia’s face when, after failing to hear from Twilight for a while, she’d read a report on the experience she had with two of her friends inside Luna’s body.