Boil water, remove from heat to cool just a bit while you measure out your coffee grounds.
Add sweetened condensed milk to a cup. Fill a separate, tall glass with ice. The more ice you use, the weaker the iced coffee.
Spoon in the coffee into the Vietnamese Coffee Maker. Wet the grounds with about a tablespoon of the hot water. Screw on the press, finger tight. Pour in the hot water and cover. The coffee will slowly drip into the cup. Use the tip of a spoon or butter knife to turn the press clockwise (for tighter press, if the coffee is dripping too fast) or counter-clockwise (too loosen if the coffee isn't dripping at all.) It should take about 3-5 minutes to finish brewing. Adjust the press as needed.
Stir the hot coffee and the sweetened condensed milk well. Pour over the ice in the tall glass.