In the meantime, I will reflect on what I have learned so far. I believe these nubs are the inferior Xenos equivalent of the female clitoris. The presence of three shows that their inferior anatomy must try and compete with the glorious human form. The interior walls seem to also be deeply studded with nerves, but not to the extent of the Xenos clitori. I would hypothesize that this shows their barbaric nature, as it suggests that females were used purely as breeding machines. Most likely they were communally shared, with a pool of females being the common property of the male warriors. Hence the need for the female to greatly enjoy procreation, females who did not enjoy the act, must have quickly left the tribe, where females who took pleasure as being the sex-slaves of the males flourished. What purpose the excessive lubrication shows is unknown at the moment, but I believe it may be due to the practice of the Xenos females being used as breeding slaves. Several males would try to impregnate her and the fact that the ones who enjoyed more men, were also more likely the popular ones among the group.
Since then the Tau have abandoned this simplistic barbarism for a new and equally barbaric idea of twisted equality (in which everyone is equal, except those who are not) that is counterproductive to a military society. In our own glorious Imperium, it is easy to see rank and even though the empire may span the galaxy, every citizen clearly knows his or her place, no matter where they may stand. This shows a weakness, as females removed from their breeding and motherly functions, now are forced to serve as warriors, a role in which they are normally unsuited for. The human female, while in general not as strong as the males of our glorious race, is still capable of being a more than competent warrior. Our flexibility for various tasks and key rank system show once again superiority, to their barbaric inflexible ambiguity.