The sucking reflex is an automatic reflex that occurs in newborns when the lips are touched, causing them to suck. It is an important reflex for feeding and nutrition in early infancy. The reflex is triggered by tactile and oral stimulation and involves coordinated movements of the tongue, lips, and jaw. The reflex disappears around 6 months of age as the infant develops more voluntary control over their movements and becomes able to suck and swallow without the reflex.