What you have to know about intent service:
"The IntentService class provides a straightforward structure for running an operation on a single background thread. This allows it to handle long-running operations without affecting your user interface's responsiveness. "
don't implement the onStartCommand method, because in case you do, you have to call the stopSelf() or stopService(), when you are finished. If you don't override this method, then Android OS handles everything.
As @Radu Ionescu mentioned, the intentService stop working, when it's done with all the request arrived to it's onHandleIntent method.
IntentService creates a default worker thread by it's on, and executes everything what arrives to the onHandleIntent method.
Just add everything to it's queue or if you need to take longer time before adding two different actions, you can use Service, to prevent the IntentService self destruction.