DD is 20wks and has only ever fed from one breast per feed.
She doesn't have a preference but everytime she feeds from the right breast I here alot of swallowing, I may have 2-3 let downs and she seems to continue to suck throughout the feed and I assume from the swallowing she's getting milk. When she feeds from the left you can hear swallowing at the beginning of the feed but not much after! What I mean by that she will continue to suck but I can't hear much swallowing! I would then take her off the left and put her on the right and she will suck and swallow for a while!! If I started with the right and try and offer the left she wouldn't tame it but if I start with the left she will nearly always take the right IYSWIM.
I hope I haven't made this confusing. I'm a little concerned that my left side is drying up. When I've pumped I've always got double out of the right. My right side always feels fuller than the left!!