Heya.
Long time reader, first time poster.
As some of you may be aware of, you can mount your mount in the Throne of the Tides elevator. But you can also mount another players mount since they count as a vehicle with two seats (You get a green "jump on" cursor when you hover over the mount).
The player who mounted the mount as a passenger have his/her seat on the "head or top" of the mount.
Example: If you mount a hawkstrider as a passenger you will stand on the hawkstriders head.
And no, I can't provide any screenshoots at the moment since I'm in school.
I think I got this in the right forum and i didn't find anything related when i searched, if not just delete or move the thread.