i was practicing with my friend one day and he did this move on me. I was taking a quick breather...and
The first scenario. My back was turned and he came from behind slipped his hand around my neck and his the inside of his elbow..ie the joint came to rest at my throat.
He tightened his arm and then slipped his free arm and cupped it around the back of my head, thereby bracing it...so i couldnt headbutt him.
What would u do to quickly and effectively stun him and/or also removing yourself from the grip.

The second scenario: again my back turned. He slipped his hands around the middle of my torso in tight vise grip. What would u do here?
I came up with my own improvisations, but Im wondering what you guys think. Thanks

stp ;)