Thank You Darwin: Phallus Evolution

My own evolution wanderings have caused me to wonder for a long time about why the human penis is structured the way it is.
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It's Darwin's 200th birthday this year and we'll be hearing a lot about him, I'm sure. I'm looking forward to seeing the new movie Creation, which is about his life and will include a look at his fear of reporting all he understood about evolution. Given the Victorian culture he lived in, no wonder he hesitated for some 50 years before he put On The Origin of Species out to the public.

My own evolution wanderings have caused me to wonder for a long time about why the human penis is structured the way it is. Why would evolution make the penis have a head on it, with an obvious bulbous, almost ad-on bigger part? Why does it have that extra skin, the foreskin, added to the mix? And, for that matter, why is that skin cut off (I know about the religious part, I just mean how did it really start)? I won't be covering that one.

I have some ideas about all of this and I'm hoping you'll chime in too.

Why do pigs have corkscrew penises? Why do Orcas' have bones in theirs and ends that 'grab' on to things? Why do some monkeys have barbs on theirs? I don't really care so much about these penises except that they do show that there is a vast arena of shapes, sizes and peculiarities about the phallus world. But most animal penises are straight and smooth so why does the human penis have a head on it?

If you consider the details in the shape of every male phallus you can't help but notice the head attached to the shaft. It is almost unique in the world of animals. The great, revered, male tool goes along nice and straight, for the most part, and then, right there on the end, it has a head on it - a nice generous head, for that matter, but an add-on piece non-the-less. The interior tissue is even different than that of the shaft. Some penises have bigger heads than others but, basically, it's there. There are more nerve endings near the underside called the frenulum where the foreskin is attached and around the head (the corona), and more girth, generally speaking. It's also got an interesting shape sort of like a heart or arrowhead with one side longer than the other. All-and-all, a little strange when it comes down to it.

Of course, I have a theory.

Close to the point of no-return, or ejaculation, the head of the penis actually swells. This can be felt by some women (with tight PC muscles) and can allow them to help their man learn ejaculation mastery by slowing down and reminding their lover to breathe and relax. The partners have to be pretty darn connected, though, so don't rely on just this method without practice.

Upon closer examination you can see that the upper lip of the head, or corona, is thicker than the lower part on the frenulum side. In some men it is a lot thicker. If you consider frontal intercourse positions (something that is supposed to distinguish us from many of the higher apes) then what is this thickness for? Why is it there? Evolutionarily there is always a reason.

I propose it is there for direct stimulation of the G-spot. There is no other reason. Evolution has triumphed yet again! Oh yeah, and we women are the lucky receivers of this male evolution, though we helped men co-create it. Many thanks to you evolving guys for your care in doing this for us! Seriously.

Being of the firm belief that doing your Kegel or PC muscle exercises (more on these in a future post) every day is of the utmost importance, I see a connection between these muscles, just to the interior of a woman's yoni (Sanskrit for vagina), and the head on the penis. The G-spot is located just beyond the entrance to the yoni and also just beyond the layer of muscles call the Pubococcygeus muscles or PC muscles. These muscles get thick upon adequate exercise. When they are very strong and in good shape all kinds of good Karma comes to the person who has exercised them. No leaking upon dancing or laughing, much stronger orgasms, orgasms - period, female ejaculation, exotic artist-like abilities during sex and a pelvic floor that can hold up your insides through thick and thin.

The thicker the muscles get, and the tighter the opening, the better in shape the muscles are. What happens is that a wall builds up at the entrance of the yoni that is formidable. This thicker 'wall' actually enhances the G-spot area but for purposes here let's just say that on the inside of that wall, a barrier to exit is created when her muscles are strong. As the ridge of the phallus head passes by the G-spot, on the outstroke, it gets 'caught' on the enhanced muscles and provides much more stimulation to the G-spot area. That thick ridge is there for a purpose - woman's pleasure. If the man pauses here and makes little tiny in-and-out movements it could send her into orgasm. If she squeezes her muscles just as he is at the end of his outstroke, well...

Understanding this can make a huge difference in how both lovers interact during intercourse. Here's the best video example I can give that will visually show the ridge's importance to the G-spot. Watch specifically the head of the lovely anatomically correct bone dildo as it comes back out from the ring I'm making with my thumb and forefinger.


Let's keep co-evolving! Comments and experiences please!

Suzie Heumann is the founder of She studies, writes, has authored three books and makes films about conscious sex, Tantra and the Kama Sutra. Check out Premium for the most comprehensive tantra training available on the Internet!