The taste of Thai iced tea is very distinct, strong, sweet and delicious. And it's orange. It's traditionally made from a regional Thai red-leafed tea that has been spiced with cardamom and star anise. There are many versions and recipes online. This one looks right to me (except I might want to try this with condensed milk instead of evaporated milk + sugar). It's from instructables.com, and I borrowed much of the language:
--2/3 cup Thai Tea Leaves (Go to your local Asian food store and look for “Thai Seasoning Mix” or “Thai Tea Dust”. It usually comes in a clear plastic brick-like bag, and looks like dark brown shredded tea leaves. The kind I have right now is called “Police Dog Brand Thai Tea Dust.”)
--1 2/3 cup Water, filtered
--1/2 cup Sugar
--1 1/2 cup Evaporated Milk (12oz can)
Bring water to a boil in a pot with some head space. You'll need room for the tea leaves, you'll be using a lot. When the water begins to boil, remove the pot from the heat to stop the boiling, and then add the tea leaves to the pot, stirring to moisten them. Don't try to use a tea bag, or tea ball, or anything, we are using a LOT of tea, and we need it to steep fully. Don't boil the tea! It will be bitter! Just let it sit in the hot water. Steep for 4 minutes, then carefully strain the tea into your heat resistant pitcher through a sieve or tea sock. When the tea is in the pitcher, add your sweetener, and stir to dissolve. You have to add the sweetener when the tea is hot, otherwise you'll never get it to dissolve fully. Put the tea in the fridge for a few hours to cool it down. To serve the tea, fill a tall glass with ice, and pour the tea over the ice, leaving about 1/4 of the glass empty at the top. Open a can of evaporated whole milk (NOT sweetened condensed milk), and top the glass off with it. Pour slowly, so that the layers stay distinct. Serve with a straw or long spoon for mixing!