The picture below shows the buttocks and back of a human being.
The buttocks and back are outlined in the next picture.
The penis in the following picture will be used to help demonstrate the shape similarities,
but first it will be flipped vertically and repositioned so the head of the penis is more aligned with the buttocks.
This picture highlights the shape similarity between the head of the penis and the buttocks,
while this picture highlights the similarity between the orientation and shape of the shaft of the penis and the back.
From this vantage point of the back and buttocks,
it is possible to see how the hole for the urethra in the penis matches the hole in the buttocks that is called the “anus”.
And finally a picture comparing the entire penis outlined to the back and buttocks outlined.
