Even in "humor" the behavior is concerning. Then if T were to terminate, what then? Then we get upset at T for "abandoning"? As a T recently who was seriously threatened and harmed by a client, I can say I would not engage in this game, its a risk not worth taking. I say this to urge you to say what you mean and mean what you say. Exploring limits is fine, pressing or threatening them in this way is not.