I have a 7 month old and initally it was ok for him to pee on the edge of pad because I wanted him to get into the habit of going on the pad. He would randomly pee in the middle or on the edge. But for the past 1-2 months, he been consistently going on the edge, specifically the far right corner of the pad. So half goes on pad and half goes on floor. Any suggestions or successful stories to make him go in the MIDDLE. THANKS.