I am very interested in dog behavior, I am lucky enough to work at a kennel, I walk the dogs during the week and run the playgroups on weekends. Most of the interaction is pretty predictable, it's after I come home that things get weird.
Phyfe and Earnest are both almost 3, Earnest was neutered really young, Phyfe around a year. Earnest has his own odd kind of alpha stuff, he won't fight, but he postures, pushes, and occasionally humps to get his point across. Phyfe was raised with horses, and really doesn't understand dogs. They're ok with each other, Earnest acts like he's the boss, Phyfe will let him mouth him all over, and shove him like a football player on defense, but if he does something too annoying Phyfe backs up and gives him one of his sonic boom barks, and Earnest backs off. Earnest will play bow and run around, Phyfe might run a bit, but he doesn't know "tag" or "gotcha last" at the dog park he'd rather get humans to pet him.
They got a tug toy for an early Christmas present, I thought they'd love it. Earnest's best friend, (no, Phyfe is not his best friend, Phyfe is the BOY'S best friend) Calvin,( a BIG yellow lab) plays tug with Earnest for hours whenever we see him. Well, we finally got both Phyfe and Earnest clamped on to either end of the toy, they started pulling. I thought finally they'd have something to do together. Earnest started play growling, to him that's a big part of that game. Phyfe dropped his end, barked, and went downstairs to Levi's room with a squeaky thing- which he proceeded to de-squeak.
Earnest doesn't go down there, he stood at the top of the stairs waving the toy forlornly, then dropped it in the hall and got his Gallileo Bone. Now nobody wants to play tug, not even with people. That toy has become "no man's land" and neither one will touch it.
Silly dogs!