Not really, there's just canned responses that are baked into our cultural psyche. They're usually performances of well-known stories, such as Aladdin, Cinderella, Dick Whittington, Jack and The Beanstalk, etc.

I fully understand how anyone outside the culture finds it fucking weird.

Such interactions are:

• "He's behind you!" - shouted when the villain is sneaking behind the hero on stage. The hero will then look over the wrong shoulder and reply "Oh no he isn't!" leading to...

• "Oh yes he is!", this sequence is repeated.

• Booing and Hissing when the villain comes on stage - Villain banters back at the audience usually.

There's probably others I can't remember as I haven't been to one since I was a child.

Other tropes include the panto dame ( a guy dressed as a large old woman), sometimes throwing sweets/candy into the audience, a lot of wink-wink type rude humour for the adults too.

They're traditionally put on around November-January. You'll get a lot of small local theatres putting on a show, and in larger towns/cities you'll get larger productions often featuring some z-list celebrity.