The "down" wing, this direction goes against any theory of flight ideas you would normally apply regarding lifting a wing with the rudder on a swept wing machine (it's because the autopilot is engaged) The technique appears to force the autopilot's hand by worsening the wing drop to take the broad roll null beyond the null margin. i.e. to an amount of roll that registers with the autopilot, in order that it can correct it with a roll input in the opposite direction and thereby lift the down wing.
This happens because the autopilot is using aileron to correct a constantly changing heading due to the out of trim rudder.
With wings level and an out of trim rudder, the aircraft will gradually turn. The autopilot senses this and does the only thing it can do, turn in the opposite direction by banking. By trimming the rudder you remove the heading drift and the autopilot removes the bank in response.
(This all assumes the autopilot doesn't have direct rudder control beyond a simple yaw damper.)