yea, they had all kinds of interesting ways of "skinning the mule".
Most ALL of which I'd be wanting to avoid.
Think of splitting a hot dog lengthwise like you do when you're going to cook it.
AFAIK, without going back and finding the info, sub incision
was done later in the adult male's life as opposed to like 13-14 YO. Which leads some to believe it was somehow related to the idea of birth control. One practice amongst many Aussie tribes was that they would marry off the young women to the older men and the younger men off to the older women. One result is that the young women would not get pregnant because of the sub incision and neither would the old women because of the menopause thing, PLUS the elders each got a nice young mate (or several) to take care of them in their waning years. Once the younger ones got older and their respective spouses died off they were allowed to marry their own age and then produced children. Interesting setup if you think about it. Pretty sensible, but these were uncivilized savages, what did they know?
Yes, there were lots of incidents of youngers hooking up on the side. This was frowned upon by the elders and in many cases resulted in either the flight of the couple with warriors in pursuit or the deaths of the individuals outright before they had a chance to run.