"I sometimes use milk instead of water. It makes the smoke thicker.
"Some people use wine. Lemon water with ice cubes is good if you want a smoother, mellower smoke."
The shisha water pipe, variously known as hookah, hubble-bubble, baraku, maraku, rguila, guza or nargile (pronounced "nar-geelah"), is one of the most evocative symbols of the Arabic world. More than 1 billion people throughout the Middle East are thought to be regular smokers.
The shisha is said to have originated in India in the 16th century when it was invented to smoke hemp oil for anaesthetic purposes.
The first pipes were made out of coconut shells, "narcil" being a type of coconut found in India. Ancient forms of water pipes have been found in Kenya and Zambia.
By the 17th century the pipe had reached Iran and Ottoman Turkey. In Iran, oak charcoal was used with pomegranate juice in early pipes called "dakkas". The Persians developed porcelain flasks and added the "marpic" or hose. Today, you can have either a single, double or triple-hose hookah.
There were no coffee-houses in Turkey until the reign of Sultan Suleyman the Law-giver, but the pipe became an important part of Turkish coffee-house culture which boomed during the reign of Murat IV (1623-40).
Soon the pipes became valued as objets d'art and craftsman were commissioned to come up with elaborate and ever more expensive designs, using gems and precious metals. No high-society Turkish home was without a water pipe. Socially, there were even rules governing the correct way to light and smoke a pipe. It is still considered rude to light your cigarette from someone else's hookah.
The water pipe's mouthpiece was traditionally made from amber because it was thought to repel germs. Today all mouthpieces are plastic, although in Egypt most smokers have their own silver mouthpiece. They leave their pipes in the cafe where it is looked after by a professional shisha valet.
In Turkey, place names like Marpullulkar derive from times when they were the home of professional pipe-makers. Beykoz is still a well-known centre for making the glass bowls used in water pipes. Ankara's Ethnographical Museum has a collection of coffee-house water pipes dating back to the Ottoman period. Cairo Museum also has a small exhibition.
Although Swedish scientists are now studying the effect of shisha smoking on oral health, there has been little or no research on the side-effects of habitual smoking. Some say that smoking one bowl of shisha is the equivalent of smoking 18 cigarettes. Others say that because water pipe tobacco is washed and filtered, you inhale less carbon dioxide and 20 times less tar than smoking a cigarette.
The hookah is still inextricably linked with drug culture, synonymous with head shops and bongs. Many cities like New York, Paris and London now boast gimmicky shisha bars with names like Hook-up Lounge and Cloud Nine.
In Tunisia, water pipes are banned from outdoor cafes or terraces. In 1993 they were banned by the Emir of Sharjah. Thailand is planning to follow suit, fearing that shisha smoking encourages cigarette smoking. Morocco is one of the few Arabic countries that does not have a shisha culture. Small "shebsy" pipes are smoked instead.
Curiously, one of the most famous literary advocates of shisha was the large blue caterpillar sitting on top of a mushroom in Lewis Carroll's Alice in Wonderland. The artist Ingres depicts a hookah pipe in his Odalisque and the Slave, as does Degas in one of his paintings.
Shisha pipes have recently even become political weapons. More and more Arabic women are smoking them in public, claiming it is a way to express their independence.
We continued to puff away at the El Fishawy cafe. The queues were not getting any shorter.
"Cigarettes are for nervous, competitive people who are always on the run," one Arabic man told me, his pipe gurgling beneath him. "Hookahs teach you patience, tolerance and the appreciation of good company," said another. His friend tapped me on the shoulder. "Smoking's an ancient cultural social practice promoting social peace. Conversation flows easily."
"So does time," added one of the waiters with a smile.
Riddell, the English teacher, nodded and adopted a learned air: "Shisha without coffee is like a sultan without furs."