I have 2 male dogs. Rick is a 6 year old Boston Terrier.
Jeff is a 3 year old Bull-mastiff. They have been together since 2009. Over the last month or so, Rick has begun humping Jeff's head on a daily basis. In addition to the humping, Rick will lick Jeff's privates until Jeff gets a "pinkie", and at least once until Jeff "finished", for lack of a better word. We only know about the finishing part because my wife caught them just after it was done yesterday.