Supervised, calm play between Luca the senior AmStaff and Sedona who is a bust dog. Luca is a little unsure of Sedona's energetic play style but he wants to engage and she is respecting his boundaries after he gives a little "that's rude" growl early in the vid. Notice that Luca "shakes off" at one point. That is an indicator of mild stress (not all stress is bad, remember) but since his overall demeanor is relaxed with a softly wagging tail and overall inquisitive attitude, and Sedona is not overwhelming him, I allow the play to continue.
Shortly after the video ends, I break the dogs and let them take a time-out. Even though this session went beautifully and both dogs were appropriate, I chose to interrupt them after a short while to "end on a good note". This is opposed to allowing them to continue on until someone gets tired and cranky, and hurt feelings ensue.
(Ignore my "omg" in the background - I was responding to someone I was talking to on the phone while taking this video ;-) )