Pegasus Whistle

Pegasus Whistle is an other item. When used, it awards the Pegasus mount.

Source
Pegasus Whistles can be obtained by exchanging 99 with the following vendors:
 * Spoils Collector - The Goblet, The Lavender Beds, Mist, The Pillars, Shirogane

Pegasus Whistles can also be obtained during the Moogle Treasure Trove event by exchanging 50 with the following vendors:
 * Itinerant Moogle