Cassius I think you're leading right up to the answer to your question. The best way to discuss pleasure, pain and neutral is by leading with the sensations and feelings, not by leading with logic. As it's playoff season in many sports right now, think of it as making use of the home court advantage. Cicero and his ilk have claimed the home court and are refusing to play an away game.
Rather than play Cicero’s game, we could design an exercise to lead through a Canonic process. Ask if the person is in a neutral state at the moment. If not, what are they experiencing and how would they describe it in terms of pleasure or pain? If they say that they are in a neutral state, ask them where they typically feel pain or stress in their body. Then ask them how that spot feels now. Is it neutral? Whether yes or no, have them try relaxing the spot and describe how that feels. The idea is to get them to experience the subtleties of the feelings, and then to understand that they are guides. It all begins there, and that's where the argument should begin. We need to get back on our home court.