Based on sculptures I have seen.
A serpent that looks like it is
swimming partialy under the surface that it is resting upon.
mount the head followed by the largest loop in descending size to the tail.
I put magnets on mine.
These are very strong for their size : http://www.harborfreight.com/10-piece-rare-earth-magnets-67488.html
I used 3 for the head, and 4 for the 2 big loops (2 per pad) , 2 for the small loop(1 per pad) and one for the tail.
Weaker magnets are sold at staples http://www.staples.com/Staples-Business-Card-Magnets-50-Pack/product_470690. I would not recommend them for the car,
will hold for a refrigerator etc. They have the advantage of peel and press application and are thin.
the head was modeled in sculptris.
Body, tail, and the "splash ripple base" were made in truespace 5.
freestanding the tail will be a problem. if you want them just loose
you might want to clip the tail to make it more able to stand(it does stand, but it is off balance.
If you have thin rare earth magnets, those are the best for this.
i put some on my model with epoxy and i will be driving my car with a serpent on the hood without concern of the wind blowing them off.
I posted the pic of the magnetically attached to my truck as a hood ornament
spray painted silver. I put rare earth magnets on it and they hold well. (I drove at highway speed without them budging)