“If his eyes are a bit too hot, a bit too bold, this is still a matter of interpretation. If the girl doesn’t like it she has only to be rude and move off. But why shouldn’t the girl like it? Mike is flattering her with his attention. In effect he is saying, ‘You interest me. I want to know you better. You’re the only woman here I care about.’
For, in addition to his flattering attention to this woman, Mike never makes the mistake of spreading his interest. He narrows his focus and speaks to only one woman, and he makes the impact of his body language all the stronger for it. Half the time, when Mike leaves with the girl of his choice, she hardly needs any persuasion. By that time a simlpe, ‘Let’s go!’ is enough.“

Oh, the treasures one finds in other people’s book shelves. Here’s Body Language by Julius Fast from 1971.  Relax, but pay attention. And you might find out who will leave with whom.