also for a funny version of experiencing it once there was what felt like a short person or a child crawling ontop of me and trying to choke me or something and i got really mad and started choking it because of this

then it felt like the thing panicked or whatever and grabbed hold of my junk and started pulling hard(not the plesant way) , but i was so mad i was not going to let go, ended up with me waking up and realising i was sleeping on my stomach and my junk was in a rather uncomfortable position

so for all i know it can just be our minds/body feeling something while we are sleeping and translating it into a story.