Waste of time and your arm trying to strangle a dog.
If you are unarmed against somthing like a rottie,and he's closed with you, believe it or not, I'd ram my hand down his throat till it came out the end. You can't change your mind halfway though. You can't take your hand out until he drops and you have to keep pushing all the way to your shoulder if need be, or he'll be able to bite.
He can't bite if he's gagging on your forearm. Watch one puke and you'll notice how their jaws automatically widen. Gag reflex forces their mouth wide open.
Hope you never need that advice.
I thought I was the only one to do that...