Vacation is signed exactly like trip or holiday: open both hands, palms facing each other, and rest them above your chest around armpit level, as if you're tucking both thumbs under the top of your overalls and just relaxing. Then move your hands forward and back, touching your imaginary trouser tops with your thumbs a few times.
Teach your baby or toddler this sign when your family is preparing for a spring or summer vacation, whether it is to a mountain getaway or a beach resort.
Use the vacation sign when you are trying to expand your baby's vocabulary. Do it contextually as your family begins to prepare for family vacations related to seasonal holidays.