I am really curious about this. My DS is 4 months old, and has never really been a sicky baby - he has done more than posseting but it has been rare. Anyway, when he was younger, all sick (possety or an hour or so after a feed) was very thin and watery, but recently (over the past few days) his sick has been thicker and looks like a FF baby's sick.
Is this something to do with the milk changing as he gets older? He is still exclusively breastfed - has never had formula or solids.