you should see buster with the rescue pitbulls in the dog parks.... buster seems to have a really good way with rescue dogs of all nature (especially big scary ones) where he gets them to play with him - the owners of the random rescue dogs are usually surprised. Its wrasslin followed by running at full speed in circles rinse and repeat until the large dog gets tired.
i guess it started when we did the puppy kindergarten* with him at 3.5mths.... there were some pretty big/vicious dogs in that class english bull terrier/pitbull/rotti/cane corso and they were just going at it from day one. The trainers actually told us to let them "fight it out" and solve their issues by themselves and rarely separate them by force.
*puppy kindergarten was kind of ridiculous in retrospect, because it was more for the owners than the dogs themselves (plus my wife wanted to do it so I didn't really have a choice). but it was nice to learn how to keep the dog behaved around people/kids/other dogs. the second he gets into a dog run, and you pat his side and say "go play" he turns into another character altogether.