1. Human penises USED to have spines. No one is sure why they disappeared, but it was before modern humans and Neanderthals split to go their own ways. Cats and rats [among a few] still have penile spines, though once castrated these apparently seem to disappear in some cases. Interesting.
2. According to urban legend if you plan to swim in South America, particularly in the Amazon…watch out guys. The Candiru, a small, scaleless, eel like catfish loves to swim up the urethra. Once there it uses its spines to keep itself firmly in place so it can access the blood supply. Possible side effects of this happening include inflammation, bleeding and the big one…death. Is it true?? Hard to find any real evidence but if you are there, and want to pee, maybe do it inside…just in case.
3. Diphallus is a rare congenital anomaly where the penis [or the clitoris apparently] comes in two. Usually only one functions properly apparently, and the second one is not always fully formed. I gather from the literature that most men are not pleased with having double the capacity.
4. Angel Lust is a postmortem erection. This has been observed in men who have been executed, particularly in hangings. Which is thought to be behind the trend to indulge in auto erotica. The Roman Catholic Church is said to have suppressed art images of Jesus Christ on the cross with an erection that were painted in the Renaissance period.
5. I shall never look at the humble corn flake quite the same again. Dr Kellogg is said to have spent a great deal of time and effort in producing food that would not only be nutritious but that would decrease any interest in sex. He considered that all disease stemmed from sexual intercourse and was determined to save the world.