Teach your baby the signs for the words in and out in baby sign language with the following descriptions and videos.
Form a sideways letter C with one hand. Form the other hand into a signed letter B with the fingers slightly bent. Place the fingers of the letter B in the center of the letter C. Remove the letter B from the letter C.
Beyer, Monica. 2006. Baby talk: A guide to using basic sign language to communicate with your baby. New York: Jeremy P. Tarcher/Penguin.