Basically, it is impossible to travel in Morocco without drinking tea. Expect being invited to the traditional Moroccan mint tea while in the country, because it is how Moroccan welcome people.
On the picture above, you have Zaid, a friendly Moroccan guy serving tea in the desert. Expect your experience in Erg Chebbi dunes to overcome any of your trip expectations, this is undoubtedly going to be the best holidays of your life. Welcome to Morocco.