I thought that you might enjoy seeing a video of Hachi playing with other puppies. We've been attending several puppy socialization classes each week, giving Hachi the chance to play with puppies his own age.
These puppy socialization classes are thought to be really important, even for puppies who have adult dogs at home who like to play with them. Adult dogs grant special "puppy license" to be wild and don't always speak up when the puppy is too rough. Other puppies are far more likely to make it clear when a puppy is playing too rough.
Besides that, it's just plain fun! Enjoy the video of Hachi in his classes and then a clip with Shyla.