I wouldn't mind a heavy flow of anything hahah...
But in all seriousness! It's basically where, from what I understand, your frames are simply getting filled rapidly and where there is more coming in than is being consumed! so basically, again from what i understand, chuck heaps of boxes on when a flow is happening because the nectar will pour in and then, as the flow dies down, the excess will be ripen in to honey which you can potentially extract