What kinds of knots work for partial hanging?

[picturesofyou]

I want to CTB tonight by partial hanging. I'm using an extension cord because I don't have access to rope, which unfortunately means I can't really tie it into a noose. Will double knotting it around my neck work? I already tested to see if it will hold my weight and it did. I'm just scared I won't pass out for some reason and people will notice the marks on my neck. Really not trying to go back to the hospital again.