It's a defect, but it's completely normal. There's this extra muscle that keeps this down, but the only way to cure it is if you cut it when you are an infant. The surgery would be more complicated as an adult, and most don't go so well. But the downward penis still works as well as any other. The advantages is being able to go down a woman's throat easily, and the doggy style hitting the G spot. Missionary is a minus, unfortunately.
