Pinkie Pie got sick (maybe from baked bads) and she's been alone in her quiet room with no forms of entertainment whatsoever, and she can't have any fun. Twi, RD, AJ, and Rarity are busy with work (or shopping, who knows), but Fluttershy isn't. So she decides to step out of her comfort zone to try and entertain Pinkie (while dragging Angel along). Seems that entertaining Pinkie has been a success.
EDIT: Whoa, this is the first pic I made that got 2,000+ favs in a long while. Thank you guys so much! EDIT 2: This is my most favorited picture now! Thank you all so much!
MLP:FiM belongs to Hasbro and was created by Lauren Faust