I'm struggling to find it too but I've had what I think is partly a success. It came from something someone wrote on one of the 'night night' threads. That is, that you don't squeeze, you push.
I was making the U shape with forefingers and thumb and feeling for the pulse in my neck. I could find it easily; above my voice box and on either side of, and 'behind', the wind pipe. I assume it's the carotid arteries as I can feel the throb under my thumb and forefingers, it's quite strong. I think where I was going wrong however is that I was squeezing - that is, as if I'm trying to close my fingers and thumb together, like closing a grip, or trying to make the U shape become an O. That wasn't working, all it was doing was 'hurting'. There was no dizziness or change in vision.
Then (after reading what someone suggested) instead of squeezing, I pushed. Keeping the U shape in my hand exactly the same, I move (push) my hand towards the back of my neck. THEN I could feel the dizziness start. I haven't yet held it for longer than 5 seconds so I don't know , and I'd guess that it'll take a little bit longer for me to black out than it seems to for other people BUT I do feel the dizziness start.
After I stop pushing, and release my hand, I feel a bit sick/nauseous. A bit 'bruised' too. I'm not pushing hard at all but I still feel it afterwards. I'll keep experimenting but I seem to be further on than I was.
