In a small mixing bowl, combine ½ cup of heavy cream with ¼ cup of sweetened condensed milk. Whisk until smooth and creamy, about 1–2 minutes.

Fill two tall glasses with clear ice cubes, about three-quarters full.

Slowly pour 1 cup of cold Coca-Cola into each glass over the ice.

Drizzle 2 tablespoons of toasted marshmallow syrup into each glass.

Add 1 tablespoon of chocolate syrup to each glass.

Carefully pour sweet cream mixture over the back of a spoon into each glass, aiming for about ¼ cup of cream in each.

Serve immediately with a straw or spoon.