Tahneek is the practice of rubbing a piece of softened date on the roof of the mouth of a newborn. The Prophet (saws) performed tahneek on many of the children of his companions, “as is narrated about the Prophet (peace and blessing be upon him) that when a child was born and brought to him soon afterward, he would moisten a small piece of a date with his mouth and then place it on the palate of the newborn”[Bukhari, Muslim and others-Seekersguidance.org]. In these modern times, tahneek is often forgotten when introducing a new Muslim child into the world. However, the Ummah should revive this practice which has many benefits spiritually and physically. In addition to the virtue and pleasure of performing a sunnah for the family, tahneek encourages a newborn as he is introduced to breastfeeding. The sweetness of the date has a soothing effect which can help to calm a crying baby before a feeding. Alternatively, the sweetness can stimulate a very sleepy baby who is hard to wake. As the finger of the one performing the tahneek is brought to the infant’s mouth, the rooting and suckling reflexes will be stimulated. The baby will lick and suck the bit of date, increasing blood flow to the mouth and exercising the muscles. He will be using all these skills when he breastfeeds. So, this gives the baby a little practice before he is brought to mother’s breast for a feeding. Tahneek also helps baby to stay awake because the sugar of the date will help to replenish energy which is quickly loss after birth. With the blessing of Allah (swt) and the help of tahneek, the baby will be ready to breastfeed.

This news is interesting, regarding to the Hadith (and what the prophet did with dates)
25 September 2013
‘Sugar gel’ helps premature babies
A dose of sugar given as a gel rubbed into the inside of the cheek is a cheap and effective way to protect premature babies against brain damage, say experts.
http://www.bbc.co.uk/news/health-24224206