- Throw the limes, sugar, and 3 cups of the cold water into a blender. 
- Pulse it a few times—don’t overdo it or the drink turns bitter. 
- Strain the mixture through a fine mesh sieve into a large pitcher. 
- Add the remaining 3 cups of cold water and the sweetened condensed milk. 
- Stir like you mean it until fully combined. 
- Serve over lots of ice, maybe even throw in a lime slice for good measure.