"I thought a thing like that could never happen to me..."
From a 1950s campaign aiming to bust the "nice girls don't get VD" myth.
While most WWII and earlier public service posters focused on the "don't get diseases from prostitutes" side of things, after the war ended, there were a growing number of men and women who weren't servicemembers or engaged in the sex trade who were coming down with STDs.
These days, syphilis is fairly uncommon. About 3500 cases are recorded per year in the US (mostly men who have sex with men), and during the primary stage, it's easily treatable with antibiotics.
Gonorrhea, though? Still going strong. Because of the continuously significant rate of infection over the years, there has been enough antibiotic treatment going on to create antibiotic-resistant Super Gonorrhea. It's a bad thing. Like all gonorrhea, it can cause permanent damage and sterility in all genders, but it's extremely difficult to treat.
Wrap it before you tap it. Don't get you some Super STDs.