For days that i'm not able to do much tummy time with 5w newborn, how can i avoid flat spots while she's on the crib sleeping at night or napping?

Tummy Time: Rotate her head from side to side while she is sleeping on her back. Also avoid putting her in swing or car seat for long periods of time. Still most important is to give her tummy time when awake and supervised.

It's a gravity thing: The skull responds to gravity pushing down on the face/head by flattening if they are always on their back.It is like a dent in a water baloon.For many months the skull is flexable and will conform to position changes.Time baby spends upright, like in a belly knapsac, cancels out some back time as does tummy time.As they begin to sit this issue starts to fade in most.