The alveoli are actually what fills with milk, and when your baby attaches to the areola of the breast and begins to suck, the aveoli empty into the milk ducts and out the nipple into your baby's mouth.
Stage Two: Buds appear, breast and nipple are raised, fat tissue begins to form and the areola (dark area of skin that surrounds the nipple) enlarges.
In this position, the mother can lift her breast and guide her nipple in any direction as she helps the baby to take in more of the areola.
Once the baby begins to suck, the mother makes sure that the entire dark area around the nipple (areola) is in the baby's mouth.
The quarter cup look fully covers the nipple and areola, but it leaves the top portion of the breasts exposed.
Stage Four: The nipple and areola become raised and form a second mound above the rest of the breast.
Sometimes the areola may get darker or the nipples may change in size or become more erect as well.
Your baby should be feeding on the areola (the darker portion of your breast), not the nipple.
Certain triangle tops don't even cover your full breasts, only the nipple and areola region.
Nipple soreness can be a result of the infant not getting a good grasp of the entire areola.