What, I find none of these methods to my taste. I don't undo ANYTHING; grab jeans and boxers at same time, pull both down, pull out. Then pull in and pull back up jeans/boxers for good measure. And I wear a belt, the belt does not hinder this process. The whole thing takes so little time that I can actually relax to start peeing before I've even pulled my jeans down. I don't recommend that for newbies, though.
It's the bonus of wearing jeans around your arse.