I have a 3w old and have shared our bed a few times on rough nights. I've tried to make it as safe as possible (no pillows or blankets near him, making sure he has space between him and DH who is a heavy sleeper). I keep hearing that babies should sleep on a firm mattress. Is this a SIDS risk? Or a developmental thing? We have a pillow top mattress, so I don't know if we need to reconsider or get some sort of addition?
TIA for any help.