“Spy on Shows” is a section where you can find all the Privates that are taking place. Users with tokens can sneak a peek into them for free the first 10 seconds (only once per show). If they like what they see, they can pay the spying rate to continue watching, which can range from 4 tokens/minute to 60 tokens/minute. It depends on the models' pricing preferences.
Note that if a spy decides to private message the model during a spying session, their identity will no longer be a secret to the model.