I was out walking the other day in the forest and we came across Max, a standard poodle. He was with his Swedish owner. We had actually met before so it was normal the dogs immediately started playing. They are approximately the same age.
In play dogs imitate wolf behaviour. Dogs like wolves convey the rules of the pack through body language and use it to express themselves. In this last picture on the left you can see that Max is the more dominant male or the more high ranking in the pack. Ozzy adopts a totally passive and submissive position by drawing his paws into his body and by exposing his neck, chest and abdomen, the most vulnerable parts of his body. Ozzy probably comes across as an unruly and boisterous adolescent. No aggression was shown in this encounter. A bit of growling on the part of Max and a bit of whimpering on the part of Ozzy. The dogs parted amicably as did their owners.