Although if you find you have to, then a good tip for making them more cooperative is to take them out of their comfort zone. Sitting them on top of something tall, with an increased risk of falling from a great height, tends to remove any temptation towards giddiness, and with any luck, you'll find your 18lbs. of pure love rooted to the spot.
Bacon is a very busy dog, he takes the role of guarding the property very seriously. However, it only took four feet of elevation to persuade him to sit still, and he was quite happy in his new position on the watchtower, and he enjoyed his break from patrolling the perimeter.
I didn't have good light for this, and although I did use a reflector to the left, I really could have done with another to brighten up his dark eye. He was getting a little bored with my constant calls to turn around so I could focus, there was far more interesting stuff going on over the fence. In the end, he proved to be quite a cooperative subject...
This was taken on the 450mm again, 8x10, magnification was approximately 0.3x. If this was taken on a DSLR, you might call it a macro... Focus was good, between his snout and his ear, the tip of the nose is a little soft, but that's ok. In the video, you can see the rear movements I used to get his coat in focus. You can also see the amount of movement there is on the rather inappropriate tripod without the rear monopod supports. Luckily, everything was still at the time of exposure.
The picture didn't take very long to make, again I only shot one frame, and quite soon Bacon was back to normal doggie duties.