Now the answers from our dear friend, Roger Repp:
Well, I hear that my very first posting has brought about an avalanche of interest and comments. Thank you both!
With the images that Melissa posted, numbers 1,2 and 5 are mating. Numbers 3, 4 and 6 are courtship. These answers are not the result of guesswork, but rather, knowing the limitations of the mechanics of mating in rattlesnakes. While male rattlesnakes are well hung, they can not wrap around a females’ tail to penetrate their cloaca. Nope! 11 times out of ten, the tails are side-by-side when full coitus is transpiring.
The female MUST cooperate in the mating process by raising her tail in the air prior to insertion. The male must then have his tail aligned horizontally with hers in order to succeed. Once hooked up, they can mate for over 24 hours!
Learn more: here’s a story about one such 24 hour+ hookup: A very long engagement.