How about a milkshake? Sonic is pairing up its delicious shakes with birthday cakes all over the nation. When you get the Sonic app, you’ll get the opportunity to enjoy a delicious Sonic shake when your birthday comes around.
Sonic will send you an offer good for a free small Classic Shake. The offer will be available in the Sonic mobile app for you to use. No, you don’t have to bring your birthday cake with you to get the offer.