Article in English: If the person doesn't look like he or she is preparing to hug you, then you may want to back off. If either of you requested the hug, then make the person you're hugging feel safe. Act as though the two of you are the only people who matter at the moment. The best way to judge how tightly or loosely to hug is to let whomever you're hugging indicate what they want by how hard they squeeze. If they are soft, be soft back; if they like bear hugs and squeeze tightly, hug back the same way. A hug is a powerful way to communicate that you care for another person, as it can feel great and improve the other person's mood. Ending the hug too early may make both of you feel awkward. If you feel comfortable, go along with it and hug until the other person lets go or loosens his or her hold.

Summary in Chinese:
只有当你想拥抱的人展开双臂时再拥抱。 拥抱时要热情。 避免拥抱一个人太紧。 在放开手之前停顿一下。 了解什么时候给予一个长久的爱的抱抱，尤其当对方感觉沮丧，情绪低落的时候。