I remember with Seren there was one night when she fed from 6pm to about 11pm non stop. It was literally boob after boob after boob, bit of winding, boob then boob then boob. She was always a big feeder, would feed for 40 mins every hour and half for quite a while. Cally's longest has been half an hour, she usually feeds for 5-10 mins (bliss)