Last Wednesday two of the three live pooches that appeared in Pina Bausch’s Viktor did onstage what most dogs do when in a state of arousal. The incident, which elicited a great deal of audience laughter and repressed giggles on stage, would have amused the late Bausch. First seen in 1986, Viktor was the first of the many city-specific works that Bausch created and on which the current World Cities 2012 retrospective (at Sadler’s Wells and the Barbican) focuses.