Basic Obedience if she is too old for puppy class! But make sure she finds a reputable trainer

I have to agree with both marian and freedombulls! most owners think that there pups are mist behave and in reality are just lacking socialitation with dogs so when the see dogs thay act "overly happy" so if that were to be the problem, dog shows or round up a group of friends with lots of dogs and go on a walk the more sheor he see's the less they will act up. but if thats not available like david said puppy class or family dog 1 as long as they get to "play" with each other

I am curious to know what the owner feels she needs to correct while the dog is playing with other dogs? I often find that "owners" will micromanage their dogs to the point they feel that certain behaviors in play are not acceptable but the dogs are having a great time and not exhibiting any negative body language or vocalizations.
Encourage her to find an instructor that will also address behavioral issues if she has concerns. Some instructors who teach family dogs will allow for socialization and play time after class (after each dog has been evaluated.) This is a wonderful opportunity to have "play time" under the supervision of a trained eye.

Puppy class or Family Dog 1.

DL

Sorry for my simple answer but i would say the park
Dogs will correct him themselves he is till young enough