I've tried this a couple of times but neither times was I able to get it to work. Both times were laying down and I think I had my left hand hooked around the top part of my neck and my right hand forcing grabing my left wrist to appy extra pressure. It may get you to pass out in theory, but I'm sure it depends on physiology.
Also when I was in psych hospital, I also tried ripping a bedsheet in half lengthways and tying a hangman's around my neck and a hole for my foot to apply pressure. This almost work but my SI kicked in just as I felt I was about to lose conciousness.
The hand pressure I tried for 90seconds before giving up, the bedsheet thing I think I tried for around 2-3mins not sure. In both cases my SI could still force breath through but I did see shooting stars. The bedsheet one was the closest to working.
It may work for you standing up but my legs go weird when I try to do things like these.
doing something like this while lying on the floor and then standing up suddenly may work a lot better.