On the chest, he'll want to ensure there are no tufts of hair hanging out of his collar, so that can be trimmed down. Ensure that it's all fairly uniform without making it too short. Consider natural hair lines and avoid cutting them yourself – it looks unnatural. His back is one of those areas that ought to be smooth – perhaps he wants you to help out with keeping it clean and neat, or if he has a carpet back there, he may want to look into waxing. The shoulders should be fairly smooth as well. Male waxing is so commonplace these days that no one bats an eyelash when a man enters the salon, so give up any hangups about that. It's important to clean up the underarm area – but it's OK not to obsess over this area. Don't forget the backside – some dudes look like they donned a pair of pants made of hair when they take off their usual pants. Once again, ensure it's all a uniform, somewhat short length.