Toilet Wax/Teflon

I just read the Teflon thread and recall reading here about waxing the inside of the bowl. What type of wax works best in your experience? For instance, automotive wax usually contains abrasives, so I assume that wouldn't work. Are we talking about furniture wax? Also -- and forgive me if this sounds totally ridiculous -- would something like Rain-X be likely to work on porcelain?

Best wishes,

Mark H.