Derpy’s Nose Wrinkle is activated when Derpy fills it with air. That’s how all nose wrinkles work, but only Derpy’s Nose Wrinkle has a brain here. Other ponies have brainless nose wrinkles. Stallions have wrinkles that are slighty bigger, while some ponies like Celestia, Luna or Cadence don’t have wrinkles. Baby ponies also don’t have wrinkles. Nose wrinkle is designed to help a pony with excess of air in his nose. Remember to never squeeze nose wrinkles, because your pony may explode. Also, while they are cute, remember to respect nose wrinkles. In fact, many ponies worship them as their only god and savior. May the Scrunch be with you!