It is commonly known or believed perhaps  that Chaurus eggs are usually found in clusters, and some hatch others are duds..

Over the course of several months, I have studied the Chaurus, their habits, and more importantly their reproductive habits. 

This volume is dedicated to the "volunteers" without which, this would not be possible.

Anatomy: 

The common anatomy of the reproductive organs of  the Chaurus resemble almost more of a tube, as opposed to a more penis shape commonly seen in other mammals. Running with this tube, is a much smaller tube, that often goes unnoticed.  Both the primary and secondary tube seem to serve a few functions which I will get into in detail.

Exterior:

The primary tube delivers the eggs, nutrients, for said eggs.  This has been observed countless times both in manually stimulating a captive chaurus, and dissecting humanoids that have died after "natural" insemination" during the ejaculatory stage, muscles push the eggs and nutrients out, in a rhythmic fashion - think heartbeat, or drum.. thump..thump...thump

The secondary tube, given that at this time, birth happens only from the uterus in female humanoids, the exact role of this tube is slightly unclear.  Upon dissection of inseminated female subjects, the tubes leading to the uterus, were largely dilated and assuming previous works on humanoid anatomy were honest endeavors- were filled with a different substance never seen in any documented dissections performed in usual situations.  The sacs containing this liquid, as well as the tubes themselves were quite swollen and in some case ruptured.  The liquid appears to be a slightly darker or greyer color than the chaurus semen (which is a very thick, thicker than honey type substance, usually white as snow).  What is not known, is does this secondary tube actually secrete a fluid, air, or both. For reasons elaborated on later- I will suggest the answer is "both."  Shortly after the thud thud thud, the subjects reported feeling like something was "burrowing" "flailing" around, and was generally called "painful"  then, at some point  the burrowing stopped- followed by a quick, but powerful stream.  Watch one of those drunkards outside the inn pissing against the wall..  so, something was expelled quickly and with force.

Interior:

The interior portions of the chaurus, are in many ways a cross between what we  would find in humans.  In this case, what resembles the uterus, houses mostly what we believe are unfertilized eggs, which then becomes the exterior tube, aka "penis."  Subsequent sacks- resembling the sacks in humanoid males that hold semen - seem to all connect to the smaller tube that runs down the primary tube.  Also, some of these almost appear to be pockets of air..  Without the ability to tell what is air and not air, it is difficult to be 100% certain, but it does seem that there are infact pockets of air, which serve to propel the liquid down the secondary tube.

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