I Don't Get It

It was a simple question. Sunset Shimmer's automobile wasn't working, and Twilight Sparkle said it needed to be tuned. Sunset decided against her better judgement to reach out to Pinkie for help. "Pinkie Pie?" Sunset Shimmer asked when she finally was able to call the pink party pony. Pinkie was desperately trying to be serious, for the sake of Sunset Shimmer. But Pinkie wasn't sure she couldn't stop from saying a pun.

"Yeah, Sunnyset?" Pinkie giggled in her cute high-pitched voice. She began to dance around the room, hoping that Sunset would ask for a party being planned.