I mean....I guess? You would have to untie and retie the rope each time, because if you're actually tying the rope as tightly as you would need to in order to ctb, its position really shouldn't be adjustable once you tie it. But if you're still conscious, you can basically do whatever you want. If you wanted to use the rope as a lasso and pretend to be Indiana Jones before tying the rope around your sweet spot, you could do that, too.
Though I'm guessing that if you're making a post like this, then you're having a hard time finding the sweet spot...just like the vast, vast majority of people who flirt with the night-night method. And then there are problems with finding it consistently enough to overcome SI around it, and then there are problems with managing to apply strong enough, sustainable enough force around it before passing out, and don't even get me started with the fucking cornhole bags...I've been toying with writing a "The Night-Night Method is Bullshit" thread, but part of me feels like it's too spicy a thread for a newbie to write
Anyway, wishing you the best of luck in whatever you decide to do!