A next call should be made in the following scenarios:
1. When a user clicks thumbs_up or thumbs_down.
2. When the recommendation list from a previous Watch or Next call has been viewed fully by the end user.
3. If displaying a list of recommendations on the sidebar, a Next Call should be made at the end of every asset. This ensures that the end user will always have the same number or recommendations in the sidebar.
Note: When making the Next Call after a behavior update, please ensure that the call is made _after_ the IRIS API responds to the Update call.