Firstly congratulations on your little. I assume that as this is DS2 that DS one did not do this?

I know 6 hours is long, but it sounds normal to me. And I doubt it will last.

My DD fed like that in the evening on and off for the first 12 weeks. Not all the time, but from my sleep deprived memory for several days at a time when she did.

My DH got dinner and did everything of an evening while i just sat on the couch for hours. Of course as DD is my first i had that luxury - however, often got a sore butt and sore boobs and desperately tired and cried.

Do a google search for Wonder weeks and you may come up with info that can help explain. It may be a wonder week/growth spurt thingy.

In terms of supply, I do not think there is a problem. The baby is stocking up for sleeping. They do so much growing in their sleep he needs the energy.

Also when I was expressing milk before DD started breast feeding (she was premmie), the evening express was regularly less than at other times of the day. I do not know if that is the same for bf or just an express thing. But could be a reason babies feed more at that time of day. (i could be wrong here)

I do not think you are doing anything wrong by letting DS2 feed like that. I demand feed and believe it is best for the baby. Obviously that might not work for everybody and every family situation.

It does end and i only vaguely remember the fatigue now.

All the best.