Literary Genius

Pinkie bounced down the stairs of Sugarcube Corner, spotting Pound and Pumpkin on the floor. She slid a small cake between them with a smile. She had a party hat atop her head.
"Happy monthiversary," she told the foals.
Cup Cake looked up upon the introduction, and almost instinctively reached beneath the table for a triangle. Pinkie simply smiled and shook her head at the mare, though.
"No song?" Cup Cake asked, obviously a bit confused.
"Nope. I was busy. I couldn't find the time to write one up," Pinkie answered.
"You write them?" Cup Cake asked. "I thought they were made up on the spot."
"Nopey-dopey. Well, I guess I could sing something like 'It's your monthiversary, hippey-hip-hooray!'" Pinkie replied.
"I think we're good, Pinkie," Carrot Cake said, having walked into the room carrying a large cake. "Cup, could you feed the twins? We have got this huge order today."
"Of course, dear. Pinkie, watch the foals."