It’s based on the assumption that you don’t feel pain in a dream. However, you actually do feel pain in a dream when you expect it hurt. So, as RC it’s definitely not so good.
I’ve noticed that in a lot of stories there is an attitude that people shouldn’t dream. That once anyone realizes that a dream is happening, they try to stop it. And I mean, even other people than the dreamer. They’ll say “wake up, you’re dreaming!” If someone did that to me I’d be very irritated, since the fact that I’m dreaming, to me, is a reason NOT to wake up. And many dreamers in stories who realize their situation just try to wake up right away, as the phrase in question illustrates. Also, when there is a particularly strange and wild dream sequence, the dreamer will often wake up and say “no more spicy food at night for me” or something similarly negative, referring to the relationship between certain foods and vivid dreams. Every time this happens, I think how foolish they are not to appreciate the dreams. Where did they get the idea that dreams are bad? I am pleased to see, however, that this attitude is showing up less frequently nowadays.
Hehe, pinching yourself or having someone else pinch you is the worst reality check you can do. It feels exactly like it does in waking life.
I’m not sure where the phrase originated from, but I guess you could see it as meaning one of two things: “Pinch me so I can feel pain and wake up” or “Pinch me so I can become more alert and aware so I can realize I’m dreaming!”
Of course, the first one is false, but it could be a potentially interesting thing to do to remind yourself to be more aware.
On the subject of feeling pain in dreams, yeah, it differs. I’ve never really felt pain yet, even when jumping off a tall cliff (it was a dull thud, really). So I guess it’d work differently for different people.
Pain is usually an intense vibration for me. However in cases where I would anticipate great pain (Walking barefoot on glass, having millions of tiny arrows shot into my skin, getting cut up with a knife, etc…), I would experience a sickening burning sensation.
To me, while I am experiencing it, the sensation is just as bad as pain, but when I wake up I always think “Well, that wasn’t so bad.”
The pain you experience in your dreams really depends on your expectations of what you are going to feel, and whether or not you are familiar with that type of pain; my two cents.