Zest 3-4 limes, then completely cut the white pith off of the zested limes.
Quarter the limes, and blend them with the lime zest and 4 cups of cold water for 10-15 seconds.
Strain it, then blend again with ice and about three-fourths of a 14-ounce can of sweetened condensed milk (adjust to taste).
Serve and enjoy!
