For many years, the Taco Bell birthday freebie didn't exist. But thankfully, those dark days are behind us, as we now get an annual free Mountain Dew Baha Blast Freeze drink!
You'll want to sign-up first (I recommend going through their mobile app). Then, to access your free birthday drink, tap “Rewards” then “My Rewards” during the start of your bday month. Your free coupon is valid for 31 days, starting on the first day of your birthday month.