The pussy lips are depicted in a "full" condition and we wonder if it actually indicates fucking or post-fucking.  Did a woman oe shaman make this?  We have the feeling these are individual portrayals.  The line around is perhaps where the thighs converge on the pussy.  You know that famous European Paleolithic figurine of a fat woman?  This may well be the same thing, just a different form.

We have some research to do - we wonder if people came to places like this to fuck, or perhaps self-pleasure as a ritual activity?  Hopefully we can find some answers.