Everyone has two personalities(性格)﹣one is shown to the world and the other is secret and real. You don't show your secret personality when you're awake because you can control(控制) yourself, but when you're asleep, your sleeping position shows the real you. And the important position that best shows your secret personality is when you go to sleep.
If you go to sleep on your back, you're a very open person. You usually believe people and you are easily influenced(影响) by new ideas. You don't like to make people unhappy, so you never show your real feelings. You're quite shy and you aren't very confident (自信的).
If you sleep on your stomach, you are a person who likes to keep secrets. You worry a lot and you're always easy to be sad. You never want to change your ideas, and you are pleased with your life. You usually live for today not for tomorrow.
If you sleep on curled up(蜷缩), you are probably a very nervous person. You have a low opinion of yourself and often don't want to be hurt, so you are very defensive(有戒心的). You're shy and you don't like meeting people. You like to be alone.
If you sleep on your side, you usually have a well﹣balanced(平衡的) personality. You know your strengths and weaknesses. You're usually careful. You have a confident personality. You sometimes feel worried, but you don't often get unhappy. You always say out what you think, even if it sometimes makes people angry.