Mate? A tea which EVERONE drinks here. It is drunk from a gourd shaped cup, mimmicking the gourds in which it was originally served, and drunk with a pipe-come-straw. First, pop your pipe into the gourd. The end of the pipe which sits in the cup has a flattened, perforated circumferance about the size of a 10 pence coin. Its purpose is to keep the tea leaves out of the pipe. The other end is tapered for sucking up your tea. Once the pipe is in the cup, you then pad in your mate tea leaves, dry pieces to the rim of the cup. Now pour in hot water, which firstly soaks into the tea leaves, but then starts filling the cup. After a few seconds, the tea is ready to be drunk. But, as mate drinking is a communal, sociable activity, the cup is passed around and after each person has had their fill, more hot water is added from the flask, which every Argentinian worth their merit carries, and the cup is passed along.
I have seen mate drunk all over; the tour guides on the buses pass around a cup; local bus drivers carry small camping stoves lodged next to their gear sticks to top up the gourd at each stop; on long distance bus rides passengers carry their 'take away/travelling' mate set which consists of flask, plastic gourd and straw! Hikers, on finishing their 6 hour hike always unpack the mate first and a cup is passed around before the business of setting up camp is addressed.
As for the taste, think authentic chinese green tea, strong with a slight bitter after taste, but with the essential difference that mate is caffeine loaded, which may explain why Argentinians never go to bed until about 1 in the morning!