You can find Ekkrit to the open waters, east of Mithalas' entrance.
To get this you need to ride him for a total of a minute. He's not that aggressive (if aggressive at all) so just "dash" into him and grab him like you would a wall, and hang on, he'll ride around and try to press against a wall to push you off.
However even if he does, the time counts. It appears this is an aggregate time, not just a single instance. It's rather easy to get this as long as you try to get it.