When you know how to personally contact an expert in a particular
field--especially when the subject is unusual, strangely specific, or illegal. Often used when you do not want to reveal the
identity of the contact or how you
came to make the acquaintance of such a person.
Co-worker: "The
boss said a hooker took off with the USB flash
drive with all our vital code stuck up her vagina. How are we going to find her and
get it back?"
You (not wanting to talk about how you did IT for a pimp/gynecologist who owes you a favor): "I know a guy."