When I was an undergrad I nannied for a family with newborn twins. From the day those babies came home from the hospital, we joked about the potty training. Every time we carried them past the bathroom, we'd hold them facing the toilet and say, "Look, the potty! Using the potty is the greatest!" or something of the like. Mind you, these were children who didn't recognize the sound of their own names yet, but the running joke was that we wanted them to be firmly conditioned to desire potty-use by the time they were actually seated upon it. I moved out long before that ever happened, so I have no idea how the little guys (who are now like 8 or something, and presumably potty trained) did when the time came.