I know this probably sounds silly & you're all thinking "what she's having a baby"?! lol
BUT..........
Breast-feeding & Expressing....
When you are feeding your baby
Feed the baby (until full or finished) on one boob, and start from the other boob on the next feed.
but when you want to express in between feeds how do your boobs not get empty?
Say if you wanted to feed and you'd only just expressed and you wanted to feed off the boob??
my pregnancy head (36+4) is fuzzled and i can't make sense lol