5 month old puppy overly rough with smaller dogs.

[tadpole39]

Hi, my 5 month rescue puppy, terrier cross has started playing very roughly with smaller dogs and puppies. He's fine with dogs bigger than him, and plays very well, and comes away when called. BUT if the dog is small, there's lots of growling and straddling, other dogs are scared of him, he's not very big, but appears very threatening. What can I do? He won't leave the dogs alone and has to be hauled away, I don't want to be the person that people avoid!
He has just started cocking his leg, so I wonder if he's getting hormone rushes but how can I manage this behaviour?