My 17 month old DD will nap for about 40 minutes in her crib and then wake up. She's been doing this since she was roughly 6 weeks old. A couple of months ago I figured out that if I go in and nurse her, she'll sleep for another hour to hour and a half. But I can't put her down or she'll wake up and be cranky. I would really like to transition away from having to hold her for the rest of her naps, but I can't figure out how. Any suggestions?