In the Monkhouse show, Roy enters the circle on the stage exactly when he starts singing. He remains un that circle, slithering left and right, only getting out when he finished the routine.
With one exception: when he talks about the crabs walking by, he steps out of the boundaries of the circle for a second. Is this a reference to lateral thinking as a means of escaping the theatrical stage, as crabs walk laterally (and he mimes it so)?