I know we are no longer advised to say Play Fighting but what ever it is how do we stop it?

As long as both parties are enjoying it, then I don't. 

If it looks like getting silly, or it's mismatched pairs (puppy and adult or adult and oldie) then distract into other behaviour or segregate/time out.

With mine it can get noisy so annoying to the humans, so it is stopped for our benefit.  'Oi, Pack it in' works for me.

Sounds about right to me. Its when they insist on doing it in the lounge in front of the telly amd its annoying and noisy

I have 2 boys that are young and let them have supervised play in the garden, the boys love to tumble about so I only really stop them mounting each other and getting overly rough, the 6 month old still snaps sometimes so I correct him they absolutely love each other  :)

I use a spray bottle full of water to correct and remind them when they get too excited

Surely this is the most natural instinct in the world ? Yes of course if you have one large heavy dog playing with a more delicate framed one care should be taken and they shouldn't be allowed to just get on with it but between matched pups/dogs....?

It's adult and puppy.  They are as bad as each other.   It annoys the neighbours more.  I find making a noise stops it momentarily, or food.   I make a different noise each time but I'm running out of ideas.
This morning I used a whistle.
They have been alright today so far as it's quite warm.  I'm worried if it continues that they might try and play rough with other dogs in the park.