I am trying to potty train my two year old son before the next addition arrives in may. He has gone on occasion, if I catch him in time. But he doesn't always tell me when he needs to go. Sometimes he tells me after he has gone, but not before. And I don't know whether I should ask him like every hour if he needs to go, or how I should go about this. Any advice on how to get this potty training in gear?