Instructions
Position your face 1 to 3 feet in front of an infant's face. Ideally, the infant is stationary in a sitting or laying position and won't become distracted by other things going on in the room.
Cover your face with both hands, ensuring that the baby cannot see your face through them. This step is vital because, in theory, an infant has not developed what is referred to as "object permanence," which suggests that she is unaware that you are still present when you are covering your face.
Swing your hands rapidly from your face to the sides of your head, like window shutters, so that your palms are now facing the child. When your face is exposed to the child, say "Peekaboo!" with energy and excitement, and follow it with a big smile.