Imagine getting a large, obtusely shaped piece of sculpture through a doorway. In the process, one might have to turn the object in dozens of different directions in order to accommodate all of the different lumps and twists in it. During the show, it's ongoing. Moments flow into and through the body as the body shakes and worms them out. Another way to do it is through music itself.
Musicians often speak of revelatory moments on stage, moments of being.
Through his music a musician might be trying to figure out what the moment means to him while, in turn, triggering flashes in audience members. An audience member, then, might need a way to release the moment from himself through music. Drum circles have long been a staple of the scene after a show. A reason for this could very well be that it is a collective effort of expression for experiences inside of a show. Dancing and drumming are completely natural and instinctual things to do.