I don’t want an aggressive dog! Should playing 'tug' with my puppy be avoided?

Contrary to the old fashioned school of thinking that a dog that wins at tug will somehow become aggressive or ‘dominant’, playing tug is a natural behaviour that dogs in the wild practice all the time in order to eat. Domestic puppies continuously practice hunting skills and shake and ‘kill’ their toy. Teaching ‘tug’ is an excellent motivator that can be used as a game to physically and mentally tire a dog out and, later in life, as a motivator for performing a behaviour or a sequence of behaviours such as in agility or fly ball.
However, tug (sometimes unfortunately called 'Tug of War') of war IS indeed a very bad game if played incorrectly by children or adults (dog wins, growls and runs off with the tug toy). But it is an excellent one if played correctly according to the owner’s rules of take (‘tug’) and release (‘let go’) when I say so.
Tug is a collaborative activity. You are not fighting for possession of the object, but together pulling it apart, like two animals pulling a large piece of prey open so they can eat the insides.  What happens when you let go and the animal gets the toy?  Ninety percent of the time they offer it back for more tugging!  Good tugging is a give and take affair. You pull the other party for a few seconds, then you move forward and let them pull you. There is no reason whatsoever not to let the dog take the toy some of the time, and teach it to release it to you if you ask.
A game of tug, like throwing a ball or a Frisbee, is often much more rewarding to some dogs than a piece of food. Tug taught early in life teaches patience and impulse control and often helps a timid dog gain confidence. It is actually quite a sensible idea to occasionally let a timid dog win. And, if a dog has been restricted to the back yard all day, expending energy by playing ‘tug’ for a few minutes before going for a walk automatically results in a much calmer dog and therefore a more pleasant walk for the owner and the dog.