I went out with a guy who used to press down lightly on my throat region without any specific pressure on my larynx or anything, and he never completely cut off my air, if I had pulled back, I would have been able to breathe properly, but it was enough to create the pressure and the sensation. My advice would be to start very slowly and play with those sensations, and try to get as much out of it with as little pressure and full-on restriction as possible.