If your baby is drinking, sometimes too much air comes in as it swallows. Coordination problems with breathing, sucking and swallowing may be the cause. By swallowing air the baby has a fuller feeling as the stomach is filled with air, and the baby will stop drinking earlier. The air in the stomach and the intestines will form bubbles and gas, causing the baby to get cramps and abdominal pain.
If you are breastfeeding, make sure you feed your baby in the proper position.
If bottle-feeding, try to keep the teat well filled with milk and let your baby take the teat in his mouth in the right way.
You can also let your baby rest more between gulps, so that the air can collect and be expelled as burps.
Your child can spontaneously regurgitate some milk after drinking. Take note of which position seems friendlier for your little one Make sure you have a bib at your fingertips, in case your child returns a little milk.
The most common posture used for winding is to hold the baby against your chest while you are sitting upright. Your baby's head then rests on your shoulder. You use one hand to support your baby, while you gently tap the back with the other hand. You can also hit the buttocks.
Another method is to let your baby sit on your leg, with her face away from you. With one hand you hold your child and make sure that it can not fall from lap, with the other you knock gently on the back.
From angelababy In Q&A