Crabs, Public lice: get's transported from person to person during intercourse. The main symptom is itching, usually in the pubic-hair area, resulting from hypersensitivity to louse saliva, which can become stronger over two or more weeks following initial infestation. In some infestations, a characteristic grey-blue or slate coloration appears (maculae caeruleae) at the feeding site, which may last for days.
Paul: "What the fuck Steve, stop scratching your balls."
Steve:"Sorry man your sister gave me the Pubonic Plague."