If there is a broadcaster you would like to spy on, go to their account and click on "Spy On This Private Show".
If you would like to scroll through different shows, click on the "Spy Shows" tab. You will have access to broadcasters who are already in private shows.
Certain broadcasters will require you to have a minimum number of tokens before they will allow you to spy in on their cam. Afterwards you will be charged by the minute a set number of tokens to continue viewing the broadcast.
