I wouldn't say that I "can" do it. But I know how, and I have done it. It really does take a lot of work, so I don't really do it these days, but all that work I put into it has left all my current dreams in some sort of in-between state where I kind of know I'm dreaming and am pretty much omnipotent all the time. Like I can always fly, nothing hurts me, if I want people to think something they do or if I want them to do something they do. If I'd want to shoot lightnings out of my hands I can, and all that stuff. It's actually pretty great.
Also, sleep paralisys has never freaked me out since I've never experienced it without knowing perfectly what's going on. I can usually open my eyes, but not move anything else. I usually open them, look around the room, then close them again to start dreaming.