Relief
Celestia's sun was starting to set when the party to celebrate Shining Armor and Cadence's upcoming foal was over. The parents-to-be went off to spend some time alone, leaving Twilight and the others to walk back to the castle by themselves.
"Man, that was a blast!" Rainbow Dash was crying as she hovered along the ground.
"Indeed," Rarity agreed, "I'm so happy for Shining Armor and Cadence. To think they'll soon have an adorable bundle of joy."
"Yeah, well, I wish they hadn't used my birth certificate in their surprise" Applejack said in an embarrassed manner.
"Oh, I can hardly wait to see what the foal will look like" Fluttershy was gushing, "Do you think it'll be an alicorn or a unicorn?"
"I'm not really sure" Twilight admitted, still ecstatic over the reveal that she would soon be an aunt, "But I guess that's just another surprise awaiting us."
One pony, however, who wasn't talking, was unusually quiet. Pinkie Pie was still getting over the release of pressure she had been under from keeping the upcoming foal a secret. And hearing Twilight say the word 'surprise' caused her to involuntary twitch.
"I have to say," Twilight suddenly said to the party pony, "you did good back there, Pinkie".
Pinkie Pie smiled, "Well, I have gotten the art of party throwing down to a science, after all. And let me tell you, cracking the cupcake code was difficult. Did you know how many mathematics went into the formula for the perfect cake batter?"
Twilight just smiled, "That's very interesting, Pinkie. However, I wasn't talking about the party."
Pinkie Pie stopped. "You weren't? Then what were you talking about?"
"Keeping Shining Armor and Cadence's baby a secret."
Pinkie Pie's eyes went wide. Then a sound like a sonic boom that woke up even Discord in his pocket dimension erupted.
"WHO TOLD YOU THAT?!!"
Twilight and the others backed away as Pinkie Pie began to twitch and shudder like she was finally turning into the psychotic mare that rumors said would happen.
"Who learned the secret?" she was frantically saying. "Was it that foal at the schoolhouse? I knew something was shifty about him when he asked for a baby foal made of balloons. You just can't trust..."
"Pinkie, calm down," Twilight held up her hooves, "Nopony told me. I just figured it out myself."
Pinkie stopped ranting. "You did?"
"Well, it does explain your random behavior all day," Rarity imputed.
"Yeah" Applejack added, "You knew that Shining Armor and Cadence were coming to Ponyville, you acted crazier than usual when somepony mentioned foals, you ignored us all afternoon when you were making your deliveries..."
"And there's the full speed loco persona you displayed during the scavenger hunt," Rainbow said bluntly.
"Considering that you also said you knew something, we figured that it might've been about the baby," Fluttershy added.
Pinkie Pie grinned sheepishly, "Guess I should've been more inconspicuous about hiding it."
"Pinkie," Rainbow said flatly, "When it comes to you, there's no such thing as inconspicuous."
"Besides," Twilight said as she walked up to the party pony, "you did a nice job keeping the surprise all this time. We kind of figured that something was up, but we didn't know what exactly. Still, thanks for letting me find out the way I did."
Pinkie Pie smiled, "You're welcome, Twilight. It probably would've been easier to hold it in if I had made a Pinkie Promise, but I sort of went overboard with those already."
"I guess I'm sort of to blame for that," Rarity said with a guilty voice, "That big speech I made about a pony having to live with the guilt of ruining a surprise is probably what lead you to act so strangely. I guess I have a tendency to be overdramatic sometimes."
"Sometimes?" Applejack quipped, causing Rainbow Dash to snicker while Rarity shot a look at Applejack.
"Keep that up and I might just make the photo on your birth certificate a centerfold of my next line," the unicorn threatened the farm pony.
Twilight came in again, "The point is, Pinkie Pie, I'm grateful for you're trying to keep the secret. You really are a true friend."
Pinkie Pie felt a huge weight and pressure lift off her which was replaced by gratitude towards the princess of friendship. "Anything for a super pony friend like you."
As the six ponies proceeded down the road again, Pinkie Pie sighed with relief.
"I'm just glad it's all over and I won't have to go through keeping a big secret like that again."
At that moment, however, Rainbow Dash and Fluttershy stopped, looked to each other nervously before turning to face Pinkie Pie while Twilight, Applejack and Rarity continued on their way.
"Why are we stopping?" Pinkie asked the two pegasi.
"Well, Pinkie," Fluttershy said slowly, "during the party, after we realized that you were keeping Shining Armor and Cadence's new foal a secret, Rainbow Dash and I talked."
"We figured that since you did such a great job keeping their secret, maybe we can confide ours in you," Rainbow Dash added.
"However, you can't tell the others yet until Rainbow Dash and I are ready," Fluttershy said pleadingly.
"I Pinkie Promise" Pinkie Pie saluted before doing her trademark pledge, "Cross my heart, hope to fly, stick a cupcake in my eye."
Rainbow Dash gave the party pony a strange look, "I thought you said you were overdoing Pinkie Promises?"
"Eh," Pinkie shrugged, "how could one more hurt? So, what do you want me to keep secret?"
Making sure nopony else was around, Rainbow Dash and Fluttershy moved in closer.
"Well, you see," Fluttershy whispered softly, "Rainbow Dash and I, we're kind of....dating."
Meanwhile in his pocket dimension, Discord was finally getting back to sleep after a glass of warm chocolate milk, only to be awakened again by another sonic boom-like yell.