We may have another tummy sleeper on our hands...
Nolan's number one choice for sleeping is upright on my chest, preferably in the Ergo. His second is on his tummy (just like Emily!).
He often falls asleep across my legs after I have burped him!
Today, after burping up over my shoulder, I laid him across the Boppy nursing pillow and this is how he slept for 45 minutes.
He sleeps on his back, completely flat, at night but I'm going to guess that he will probably flip over to his stomach in a few months once he's strong enough and in his crib.