By the way it positions it's body. by snarling (showing its teeth in warning), growling or by wagging its tail. I also had a dog that learned (from humans) to smile when greeting you.
Without emotions, we'd have no ability or desire to communicate with other members of the Human race. We'd have no signals for pleasure, negativity, no drive to reproduce or experiment...
A havanese (or any dog) might be eating/chewing on their tail for many reasons. The dog could be just bored and have nothing better to do. A better answer is that the tail probably itches, and the...
well, you have to make them have sex first. the way you do that is to put them alone in the same room, turn the lights off, put some "bow chicka wow wow" kind of music on, and just let the magic...
2nd Answer: Find an all breed dog club in your area and join it, they will to guide you in what to do. The will also probably have confirmation classes to help train you how to show your dog...