DS is 6.5 mo. He used to only take 30 - 40 min naps (A time is 3hr). Now that he's decided to be a tummy sleeper, I'm able to extend his naps by patting him on the back. But I have to do this for almost every single nap, or he'll be up after 30-40min. Is that to be expected at this age? When might he be able to get through sleep transitions on his own? Am I going to make him dependent on me patting his back to take long naps?