Notice in this video:
The baby’s jaw drops in a reflex response to being up close to the breast and nipple. The tongue does not act independently but follows the jaw as it drops down and comes up. A vacuum is created inside the baby’s mouth, so that more and more nipple and breast tissue are drawn up into the mouth as the suckling continues, until the little one’s mouth is wide open and full of breast tissue. If we can see the baby’s lips, we known the baby doesn’t have a nice deep face-breast bury, and this may cause problems like nipple pain or fussiness at the breast.
This baby is less than a week old but is drinking happily. You will see that although she has delicate breasts, this mother is producing lots of milk. She has been feeding her baby frequently, to cue, since his birth. This tiny one manages high volumes of milk during the letdown very well, because of his excellent positional stability. When babies pull off the breast, it is not typically because they can’t manage the letdown, but because they aren’t stable enough
It’s worthwhile looking at a number of videos of a baby transferring milk efficiently. Not all of a breastfeed goes like this, and some babies take time to get started with the feed. They need pauses at the breast to catch their breath, and we don’t want to hurry them. Some feeds there is lots of milk transfer, in feeds very little. Some feeds are longer, others much shorter. What matters is that you offer the breast frequently and flexibly (perhaps 12 times each breast in a 24-hour period, without looking at the clock!).
In this video, the newborn is drinking well. If there had been any problems at all, he could have been snuggled back a few millimetres in the direction of his feet, so that his upper lip was even more buried in and less visible, with less gap between the breast and his nose. Then his jaw would have dropped even deeper with the chin buried into the breast, and even more breast tissue would have been drawn up into his mouth. Notice that the ratio of sucks to swallows is unpredictable and irregular, which is normal. Never worry about counting sucks and swallows!