Your BB may just take a break, you can wake him up by "So Fung"...etc. Don't worry, even you feel the breast is empty, when BB suck, there still have drop coming out, more stimulation more supply ma, they just need more time. Before, my BB on & off suck for whole noon, when tired he may sleep for 30mins, then start to work again, they are very hard working in deed.
On average, my BB suck 15-30 for 1 side, sometimes need eat both sides. So he maxi eat 1 hr.