Are you also crate training him? how big is the puppy - can you lift him and shove him inside the crate when he is behaving undesirably? I have two puppies at 4.5months (45lbs each). The vocal one gets aggressively playful with his sister and thats when I pick him up, shove him inside the crate. At this point, he usually likes to get vocal (bark and whine) with me; so I ignore him and when he quiets down, he gets a treat and I walk away (barking and whining continuing). I keep him in there for 10-15mins and if he continues with good behaviour he gets a treat and gets to come out. This is only successful, if the crate is also being established as a safe space and not just a punishment event. My puppies sleep in their crates just so they can sleep without getting woken up by the other one in the middle of the night because their foot was bitten. If the crating doesnt work, try the shock collar. Its not as bad as it sounds and you can teach a desirable behaviour fairly quickly. Just dont make it a crutch and use it for EVERY thing. Find one behaviour and work on correcting that. Then once thats set, work on another behaviour. Shock collars are not electrocuting the puppy, they are used for sporting and training and have plenty of advantages when used correctly. I am using this when the play gets mixed with growling and snarling. Another alternative is to hit him (firmer than a tap and gentler than a whack) on the nose with a FIRM "NO" and big eyes. Not the top of the snout, just the nose. Thats a sensitive area with a lot of nerves and he'll get the message. if you dont want to use your hand to smack him, use a rolled up newspaper. I promise I am not a horrible dog person. Positive reinforcement was only going so far before I lost my shizzle in the middle of the night. I talked to some hunting trainers and they guided me. Hope this helps - good luck!