Take a PizzaBoy or a Faggio to the airport and go to the end of one of the long runways. Build a wee bit of speed and go into a stoppie, then try and slow down as much as you can without finishing the stoppie by taking your finger off the X button briefly. Then hit it again. You should now be doing a very slow stoppie. Just keep going to the end of the runway. Because you're going really slowly, it should be easy to keep the bike in a straight line by tapping left and right when it starts to twist and turn.
That's how I got my 216 second stoppie anyway.
KM.
