We practice in the air on FI courses by banking from (30 degrees) left to right very quickly and keeping the nose on a constant centreline with the rudder. I am always amazed at how few pilots can do this when they first try it.
In the states we call it dutch rolls. Very useful exercise. Both my primary instructor in the PA12 and my acro instructor in the S2A had me do this. A couple others along the way too.
-- IFMU