Koda, three-year-old Boxer and Mukki, 18-month-old Boxer, mating, in October 2011. This will not result in any puppies since Koda has had a vasectomy. This is Mukki's second heat cycle. They mated several times on the first (video of one here:
Part 1 www.youtube.com/watch
Part 2 www.youtube.com/watch
This video would have been more than twice as long had I included their "foreplay." They like to play, chase, box and hump each other for quite awhile before actually mating.
Here are links to information on health effects of spay and neuter in dogs: Despite what so many people including vets say, it is not the best option for their health.