All of our dogs have been well behaved, but also spoiled rotten. Like Shani's kittie, when my Rottie wants to play it's now. He gets this goofy grin on his face and he gets his whole body wagging back and forth. If that doesn't do it, next comes the insistent woofs. If I'm foolish enough to not comply at that point, he tries to push between me and the computer or takes my wrist in his mouth and gives me a tug. He wins every time.
He also is good at getting tummy scratches on demand. He'll walk into my office, get my attention, and fall to the floor and roll onto his back. It's almost like the "help, I've fallen and can't get up"...What a clown.