Here are some signs your baby is latched correctly (or incorrectly). Your baby's lips form a seal over your breast. Your baby's mouth is full of your breast. Your baby's lips flange outward, fish-like, and press against your breast. Your baby's chin is touching your breast.
When a baby is latched onto the breast perfectly, the tip of your nipple will be at the PERFECT POINT. Imagine a line from the tip of your baby’s nose to his ear lobe. Right at the midpoint of that line, far back towards the root of the baby’s mouth, is the PERFECT POINT.