The word milk is the first sign that my husband and I started using with our daughter. At almost six months old, she is starting to associate the sign with the meaning. Teach your baby the sign for the word milk in baby sign language with the following description and video.
Hold the hand by the side of the mouth next to the cheek. Squeeze the fingers and thumb of the hand into a fist in the motion of milking a cow.
Beyer, Monica. 2006. Baby talk: A guide to using basic sign language to communicate with your baby. New York: Jeremy P. Tarcher/Penguin.