It’s not about the length or girth but more about the head of the penis. In fact, have you ever thought why it has a mushroom head?
Experts believe the penis evolved to become a “tool” with a ridge to remove the semen on love rivals.
Scientists have investigated the anatomy of the human penis. They found the thrust of the penis – and the ridge that separates the head from the shaft – could help clear a woman’s vagina and reproductive system of a previous lover’s sperm.
The experts tested their theory in the lab – with latex penises and model vaginas. And they found that the deeper the thrust, the better.
We theorise that as a consequence of competition for paternity, human males evolved uniquely configured penises that function to displace semen from the vagina left by other males.
“Thus, the human penis may enable males to substitute their semen for the semen of their competitors.”
They found evidence that couples tend to have more energy sex if the woman has been suspected of cheating.
A longer penis would not only have been an advantage for leaving semen in a less accessible part of the vagina, but by filling and expanding the vagina it also would aid and abet the displacement of semen left by other males as a means of maximising the likelihood of paternity.