Wash and slice strawberries. Lay flat on plate or baking sheet and sprinkle with sugar. Freeze for at least 30 minutes.
Fill (I mean really FILL) the pouches with blueberries and strawberries.
Pour sangria in pouches up to the designated line. If not marked, leave about half an inch of space below the seal to leave room for expansion.
Gently try to push out any air bubbles before sealing.
Freeze lying flat for 12-24 hours. Serve immediately.