He may also touch his own face or rub his chin if he is interested in you, according to Jeff Thompson, a communication and conflict specialist in his "Psychology Today" article "Are Man and Woman Equals in Nonverbal Communication?
In addition, women are more likely to use eye contact to gauge the sincerity of the other party.
Women also generally rely more on facial expressions to convey their meaning or the intensity of their feelings.
Synchronized behaviors show you are comfortable with each other and open to taking the relationship further.
Arlin Cuncic has been writing about mental health since 2007, specializing in social anxiety disorder and depression topics.
Couples who are flirting with one another will display behavior known as "postural echo" or "interactional synchrony," according to the Social Issues Research Centre.
You might both raise your glasses to have a drink at the same time or mirror each other's movements -- behaviors that happen completely naturally and without effort.
They are also better at reading unintentional nonverbal messages, such as signals of deception.
Although men often send nonverbal signals, they typically do so with less subtlety than women.
Watch to see whether the other person moves into your personal or intimate zone to gauge whether he is flirting.