Long time lurker, but I finally found something worth posting!
Step 1:
First you need to get the quest "Here Fishie Fishie" (Here Fishie Fishie - Quest - World of Warcraft) which will give you the quest item "Fish Hat" (Fish Hat - Item - World of Warcraft).
Step 2:
Use your "Fish Hat" (Fish Hat - Item - World of Warcraft) and it will give you the buff "Lure" (Lure - Spell - World of Warcraft).
(The Lure buff also gives you a really cool looking hat on your head.)
Step 3:
Get on any mount and people in your party can now get on it as if it was a passenger mount! (CAN BE USED EVERYWHERE AND ANYWHERE)
Can be used everywhere and can be seen by everyone!