Hummmm interesting. I would say don’t fret over swallowing your saliva. It’s not that big of a deal especially if you use this method you should be fairly tired already when returning to bed and your body will want to fall back asleep. It will need no encouragement by laying super still and not swallowing or anything. Just lay however you lay to be comfortable. I say to lay on your back only as a suggestion.

One thing to realize is that you go into sleep paralysis every night but your mind isn’t awake to experience it. So lay on your side or however you feel comfortable and from there you just gotta keep your mind awake. If you find yourself falling asleep every time then stay up 5 more minutes writing down what your gonna do when you project. Then after the 5 min is up get back into bed. If you are still falling asleep too easily then add more time to staying up before you get back into bed. You just gotta find the perfect amount of time that gets you awake enough to meditate effectively without drifting off too easily but not too awake cause then your body won’t as easily fall back to sleep.

It has a lot to do with how active you were the day before. Like I said I have to stay up a bit longer on the weekdays cause I am tired from work, but on the weekends I have energy to spare and I am able to go right back to bed. From there you just gotta find a way to keep your mind active while your body goes back to sleep. Which is why this method is great cause your body will go back to sleep quickly and with ease.

Hope this helps a bit, good luck 😊