I believe the MDX is related to the Honda Pilot, which could be towed up to about 2005, when Honda dropped the recommendation. The discussions on this forum suggested it was due to frame seperation rather than transaxle/transmission or suspension problems.
If you still want to do it, you'll need a baseplate (the thing that stays on your MDX and allows the tow bar to connect to the car), a wiring harness and connection to operate the rear brake lights, as well as a tow bar. You should also have a braking system on the MDX to help stop the combination. There are several, and some like the "box" you can put in between the seat the the brake pedal. Several of my friends have had problems with the box set up and have gone to systems that are premanent and under the hood. I use the Roadmaster 9000 just because my toad has a braking system that can't use the under hood type.