What is the purpose of a penis? Biologically. I’m not talking about sex now.
Well, basically, its function is to deliver the sperm as close as possible to an oocyte, to produce another life and if it malfunctions the owner is simply kicked out of the gene pool. Well, quite some of you guys, probably don’t care too much of becoming fathers, at least not too fast and only after fucking as many chicks as possible but most other species don’t have as much fun and pleasure from sex as we, humans, do. Though I believe that researches also study this… In a few years we may find out that much more animals actually enjoy mating as much as we do.
Anyway, mammals’ penises vary in size, shape and structure. Some of them have bones inside, you know… Men don’t have bones there, though. Sometimes we could feel sorry that it’s not the case, but the point is, that you guys have there the best hydraulic pump in the world and you just have to keep it in shape. In its erected shape when needed. To keep us, women, happy.
Here some more interesting things about penis anatomy that I found on Ted.com