Help How to make night-night more reliable? (failed twice)

[certifiedidiot]

I just tried night-night twice, but all it did was cutting off a bit of bloodflow and only made my head fill a bit swollen and red/purple. I'm using a ratched strap and sand bags for this. I also haven't been able to impair my vision or even get light-headed by cutting off my bloodflow with my fingers, even though I felt I was RIGHT on the blood vessels each time. Another thing I was thinking is that it's more difficult because my neck is a bit thicker because I'm on the heavy side, but not a lot of fat is stored there anyway. Any advice to do this more reliably?