Since I am a berber, I am very excited to give this brief description.
So what is Ahidous?
The dance involves poetic songs accompanied by traditional dances performed by the Berber tribes of the Middle Atlas Mountains of Morocco - the Zayanes - in which men and women, elbow to elbow, round and flexible form of rolling, accompanied by singing (in Berber languages izli, Izlan) rhythmic pounding to the rhythm of the earth bendir in memory of former fertility rites.
The ahidous is known to be the ultimate entertainment center of the Amazigh of Morocco, their means of expression and the most complete and most alive.
They dance at festivals, the summer after the harvest, and almost every night in the villages.
The dancers sit in a circle, half circle, or in two rows facing each other, single men, single women, or male and female alternate, closely packed, shoulder against shoulder, they form a whole. The dance is punctuated by the tambourine and clapping.
The movements are collective, but a tramp, a tremor that spreads, interspersed with broad undulations. For their comfort and together, they demonstrate a remarkable sense of rhythm. However, they keep repeating almost always the same gesture, at the same time, ahidous is mainly a collection of juxtapositions.
To read more about the subject, I recommend this book:
Ahidous