Those who recently purchased or renewed their World of Warcraft 6-Month subscription were greeted today with a brand-new gift: Squeakers, the Trickster Mount — inspired in the Lunar Festival.
Click the Gift icon at the top-right (near your Username and Avatar) to open the GIFTS window. Then Claim the gift. You will be able to choose the region you wish to unlock the gift in. In my case: Americas.
After the complete message, launch World of Warcraft. Open the Mounts Tab. You will find a Unwrapped Gift. Open it and the mount is yours.