Best thing to do is ask, main thing is try not to pull any awkward faces, try and stay neutral, don't look away just like you would with any other conversation with anyone else! But yes just ask what helps varies from person to person, it may also make it less awkward. A stutter can sometimes feel like 'the elephant in the room' Having a stutter myself I really appreciate people like you who take the time out to research and help people, thank you!