Slowly add the lemon lime soda (it will bubble). Stir gently.
Top with marshmallows, a peeps bunny, and sprinkles, if desired.
Notes
Large Batch Easter Punch: To a large punch bowl, add one carton (59 ounces) of strawberry lemonade, a two-liter bottle of lemon-lime soda, and top with a half gallon of strawberry ice cream.