The Natural Response Nipple releases milk only when baby actively drinks. Babies can drink, swallow and breathe using their natural rhythm, like on the breast. Making it easy to combine breast and bottle feeding.   Nipple releases milk when baby actively drinks The Natural Response Nipple works with your baby's natural feeding rhythm, making it easy to combine breast feeding and bottle feeding. The nipple has a unique opening which only releases milk when the baby actively drinks. So when they pause to swallow and breathe, the milk pauses too. Natural latch on with breast-shaped nipple The wide, soft and flexible nipple is designed to mimic the shape and feel of a breast, helping baby to latch on and feed comfortably. Designed to reduce colic and discomfort Anti-colic valve is designed to keep air away from baby's tummy during feeding, to help reduce colic and discomfort.