I advise you to try and act as if it doesn't exist or at least don't pay too much attention to it. Good or bad. Because even when someone tries to tell me its ok, I understand, I suddenly become aware of it myself and self conscious and stutter more. But just calmly looking the person in the eye as they speak and no nodding or as they're trying to speak, that throws me off. And please don't try to compete his sentences. . It could seem sweet but I feel incompetent when someone does that to me.