Reminds me of instructing at the CAP National Flight Academy at OSH one year. I would lay down in my bunk at night and had to put one foot on the floor to counteract the feeling of slipping sideways. The students came up with a joke: "Why to airplanes have rudder pedals?" Answer: To give the flight instructor something to say.
After a short time, you should -- in VMC -- FEEL when an airplane is uncoordinated. Or, like our glider pilot friends, you can tape a piece of yarn to the windscreen.
(I still think the best answer so far has been the Garmin 3X!)