If you pause the game you can go to the options and see the whole controller configuration. What you use to "jockey" depends on the configuration you choose, but on "classic", I think it's LT/L2. I prefer it on LB/L1 so I swap the buttons around.
How do you run fast and jostle, do you run like The Hulk? :lol:
When running there will be natural pushing movements done automatically, but when you press the jostle button you will automatically slow down to barge/push people out of the way. If you want to run and jostle at the same time you're best to sprint up to the final point of your run and then press the jostle button.