when you first go to the camp you get a vision of your master and he recites the rules Astarion has to follow. I don't remember all of them, but the important ones: not to feed on intelligent creatures, not to leave the master, and, that he is the property of the master. after the vision, you can feed on shadowheart but it seems like it always fails for some reason. well we are not supposed to have access to it yet so I can't complain about that.
