The swing sign looks two legs on a swing going back and forth. On your non-dominant hand, extend your middle and index fingers. Then hook your dominant middle and index fingers over the fingers on your non-dominant hand, and move your hands back and forth.
When you go to the playground, make the swing sign before you put your baby into the swing.
The sign for swing is associated with fun, and babies will learn it quickly. Use it when getting ready to go to the park, or if you are fortunate enough to have an indoor swing, ask your baby if he wishes to spend time swinging.