What Goes Up

Over the past few nights, the rule has been: What goes up, stays up. I walked into the nursery a few mornings ago to rescue Bry from his crib only to find him SITTING UP and absentmindedly running his hand across the crib bars, much like how I imagine a baby in jail would summon a warden. This was all well and cute and - hey! - Bry is making progress in gross motor skills and whatnot. The only problem with this achievement is that he has not yet developed the ever so important skill of LYING BACK DOWN after he has rolled himself up into a sitting position. The upshot is that two nights ago at 10:40 pm, 3:30 am, 3:50 am, etc. (the actual timing is maybe a little fuzzy), we stumbled into the nursery to find Bry crying and sitting up, unable to go back to sleep because he's upright. As soon as we calm him down, and place him on his back or side, he seems to instinctively roll onto his stomach and then sit up. Good trick for impressing the ladies perhaps, but not so helpful in the middle of the night. Needless to say, sleep (or actually the lack thereof) has been quite miserable. Anybody have any tips on teaching babies to go from vertical to horizontal?