Suffocating toys

I'm not sure how else to describe it.
Do you know when in nature programs a lion (or predator) takes down a large animal (like a zebra) and because it can't instantly kill it, it has to hold onto it's neck until the animal suffocates? I'm sure that is a crap explanation and I hope you know what I mean.

Well Cookie has started doing that to his toys, he has always been a playful dog and if you're not directing his play (fetch, tug or another game) he is normally trying to pull them apart and pull all the stuffing out. Well he still does all the normal stuff but has started doing this.
I will have to video it and upload when I can.
He holds the toy with both paws, sort of on top but at the sides (so it can't escape I guess) and then holds onto it pretty tight. He's breathing after a while sounds like a creepy man breathing down the phone line in horror films. If you take the toy or distract him, he will wait until he has the toy back and do it again.

He's never killed anything in his life, never mind something big enough to kill like this, and it just sort of started over night. Now he will do it for an hour or so and even falls asleep with it still in his mouth!

Any ideas??
He's been checked by the vet, teeth all okay. She has suggested it might have been a fluke thing he did and it releases endorphins into his system. I wonder if he does it because he gums are sore and itchy from his allergies (holding onto a soggy toy might help). My OH just thinks it's creepy, while I just can't help but giggle (I know it's encouraging him but it's so hard not to!).

Sounds like he's fixating on his toy - quite a regular thing in Staffies/their crosses/and some other bull breeds. Their single minded determination especially in prey related scenarios, both real and simulated, is one of the things they were bred for. It is in their genes and once it surfaces as it has with your chap, there is very little to stop it. One possible remedy is distraction onto something completely different and if it is just one toy in particular - get rid of it. A sharp whistle or rattle a plastic bottle with pebbles in it then remove his fixated object. Do not return it. Take him for a sharp walk or some other completely different activity, which he would normally enjoy. Doubtless there are some very fancy explanations and even fancier cures out there for this behaviour but give this a try first, it may surprise you. Good luck!

He will drop his toy and leave it if I ask him to, I'm not sure if it is actually a problem or not and to be honest unless it is causing him some problems I am unaware of it is preferable to him destroying the toys and pulling out all the stuffing. This makes a mess and I am always worried that he may swallowing bits of stuffing that get stuck to his tongue, cheeks or teeth (since his mouth is obviously wet).
He is 10 years old and has numerous health problems that means his walks are quite limited.
He does it with all of this toys, and only really likes stuffed toys. He's never liked rubber toys and will only 'play' with his kong if there is food in it, so I don't want to take them away.
I'm more interested in why he is doing it and that it isn't causing any problems than how to stop it. Like I said I can tell him to stop and he will, but if I just throw the toy or call him away he will go back to doing it. I have to tell him to stop.

If his actions are not causing you or him distress, then as i said in my previous post he is just displaying a breed typical trait i.e. Single minded determination. Hardly likely to cause him any harm, for as you say if you want him to leave it he will. Really surprised that your vet didn't mention any of this. I don't keep (and never have)bull breeds, but as my fascination for over 50 years has been lurchers, I know to avoid bull crosses, for I neither want nor need their in bred abilities. It is what endears them to many people but makes them too intractable for my taste when mixed with high prey drive running dog breeds. Bye fer now.

I wouldn't worry too much as long as it's not being directed at living things. It is pretty ghoulish to watch our dogs doing what comes naturally sometimes.

Sophie never did the headshaking that Callie does in play. But watching them pounce on a squeaky toy and play tug of war till the stuffing flies is pretty nasty if you think about if that was real prey

Just to clarify...cats kill with a bite to the back of the neck, canines go for the belly. Gah, perhaps stuff we don't like to consider with our fur babies, but yeah.

And as an after thought...for as rough as he plays it would take me being directly attacked for Callie to turn on anything human or animal. Sophie has killed many things along the way and she's the fraidy dog.

I'm not sure whether it's a particularly a bull breed trait as I haven't owned one for longer than I can remember, but if you saw my Shar-Pei playing with my Miniature Schnauzer, you'd think she was trying to murder him! She "rugby tackles" him down by holding the back of his neck in her mouth and pins him to the floor with one of her paws which looks quite horrific.

It used to worry me because I was afraid she might hurt him, but she never has and he seems to enjoy playing this way. If however I feel she's getting to rough all I have to do is tell her "gently" and she stops immediately. She only likes soft toys to play with, usually carrying them around in her mouth, or sitting on the floor, nibbling them but I've never know her to pull any of them to pieces.

It is just a dog thing. As long as he isn't hurting a living being and not destroying your house then why worry. As you say you would like to know why he is doing it. Probably because he gets enjoyment out of it and knows that he can't do it to you. Brainy dog.

Wow thank you all for the replies.
Seems that everyone agrees that it isn't causing him any harm and he doesn't seem distressed or too fixated so I shall continue to let him. I need to get my giggling under control though, him doing it for his own enjoyment is one thing but I shouldn't be encouraging it.
It's the funny breathing, like a creepy man down the phone, that gets me. And it's so cute when he falls asleep doing it.
Being raw fed we are quite used to watching him do things that used to make us flinch, like the ease at which he can bite through bones and tear off flesh, but as far as I'm aware (he's a rescue) he has never killed anything. That would be a bit too gruesome for me. He has eaten most of a whole pheasant before, had fun pulling off the feathers. What a mess!
But he only does this with his toys, and it's still a recent thing, which is why I wanted to know if it would be causing him any harm (mentally as well as physically) so I could stop it before it becomes too ingrained.

As for the vet, my OH discussed it with her, I wasn't there. He came back talking about endorphins and typical to him couldn't remember much else. So she may have mentioned bull breeds and what not, but she didn't think it was causing him any problems.