Sonata stumbles upon a little video while browsing the internet. What follows requires an incredible amount of scrubbing and therapy to repair for all parties involved.
When the Bearers race forth from Ponyville on an official mission, somepony has to take over on their day jobs. For Fluttershy, that's usually Snowflake. But he's not available today, so it's going to be a Sherman tank.
Pinkie Pie has always served admirably as Element of Laughter, and it's time for the princesses to show their appreciation. In fact, they have a special assignment, something they've never tried. It will be the best surprise she ever had.