It’s not sharing; it’s called hot bunking, where the off watch swab jockey sleeps in the bunk. They don’t both use the bunk at the same time, (but you knew that didn’t you?)
It would really be "hot bunking" when overlap occured.
I have always wondered in regards to the practice of ‘hot bunking’. Do they change pillowcases or provide for individual pillows?
Otherwise it seems like colds and flu would just rip through a sub crew like wildfire.