One thing you can do to help tackle the issue, however, is teach your dog how to offer a ‘sit’ automatically, whenever they ...

Teaching your dog to sit should not be a difficult thing. The key is to lure them with a treat into a sit, and not wrestle them into a sit. Here again you're going to have a treat in your hand ...

When dogs feel threatened they are far less inclined to learn so it's far more important that you get down on your little dog's level when you're training ... and ask them to sit.