The only way I can get Spock to nap for me (aside from the car) is bf. Everyone else (dh, my parents) she will just cuddle on the couch with them and doze off. She won't do that for me, she will cuddle me on the couch, but will either harass me for milk or jump up and keep herself busy so she won't sleep.
She lays down and sleeps at care, I asked them how they did it and got a room full of toddlers all to sleep at the same time. They said you wear them out in the morning, fill their bellies, and then turn down the lights turn on some peaceful music and make a game of laying down...and they all just pass out.