Here's an example:
Nin sleeps on her side in the fetal position, with her arms under her head.
emma is the only one who sleeps on her back. She will usually have her arms behind her head and have a very open body language, including having her legs spread and generally taking up more space than the rest. She is also very easy to lie next to, as she kind of molds to what is comfortable for both her and the SO when asleep.
Lin will fall asleep in a normal position but will usually in a matter of a short time end up either diagonally or some other "wrong way" in the bed or end up upside down with her legs up against the wall or simply half fall out of the bed and sleep hanging upside down etc.
This can be very apparent or there can be small differences. Our SO can't always tell who it is, but she can for the most part now. This has helped quite a bit with alleviating awkwardness and having our SO know if it's someone she can wake up/ if they're comfortable having her lie in next to them etc.
Just a tip for anyone who's having a hard time sharing a bed with a DID'er (or someone who has time on their hands like we've had

