The rash that a male often gets as the scrotum rubs up against the inner thighs from excessive movement. As a result, one walks similar to a cowboy with legs bowed. Thus the term, "Cowboy Syndrome."
John: "Oh my God! I think this is the worst case of Cowboy Syndrome I've ever had. My thighs feel like they're on fire.
Mike: "You better have that girlfriend of yours rub some ointment on there if you want it to get better."