To pull a Benvolio is to tell someone forget about another person they were in love with and feast their eyes on others, like Benvolio from Shakespeare's Romeo and Juliet. The person being told this should "forget to think" of the original person.
Example 1:
Person 1: I really like Ruby but I don't think she loves me back.
Person 2: I'm gonna pull a Benvolio and tell you to just forget about her and look for other beauties.
Example 2:
Jane pulled a Benvolio and told her friend to forget about the guy and look for someone else.
Example 3:
Person 1: Did you see that guy? He just told his friend to forget about his crush and go looking for another person to crush on. He really did pull a Benvolio over there.