The Privates > section in the Outliner features options for the genitals of the character. It changes based on the Gender Type.
Privates > Shaft is kind of like a specialised Part. It contains its own Coloration if expanded.
When Privates > Shaft is selected, the Properties will reveal options for the Shaft such as: The Model, Length and Thickness sliders (As well as curve editors for them), Curve Sliders and starting direction. The options here are pretty simple for the most part and demand a little bit of experimentation to see how exactly you can shape the penis.
Additionally, there is a Collapsed Advanced at the very top that reveals 2 new curve editors that can further shape the penis.
Next Page [Areola & Nipple]