Just wondered if any one knows much about this. I have found conflicting information on the internet some saying lying with a curved spine is more natural and some saying the opposite.
I know lying DD (5 weeks old) in a car seat for any length of time is bad as are some but not all slings.
We currently have a woven sling and she lies on a variety of mats at home. I also have a soft bouncy chair that she sometimes likes and she also seems to like lying arched back over my lap to look around her. 
Are bouncy chairs ok as far as people know?