- Behold: the wacky, weird, and wonderful world of duck genitalia, evolved as a result of all the duck-rape. 20cm explosive corkscrew penis hardens in 1/3 of a second and purposely confusing, maze-like vaginas. http://blogs.discovermagazine.com/notrocketscience/2009/12/22/ballistic-penises-and-corkscrew-vaginas-the-sexual-battles-of-ducks/ 6 comments reddit.com