Whether or not this tribe truly is incredibly hung, the real issue (should be) for all of us: safe PE.
I don’t believe an ADS in inherently unsafe (providing it’s not cutting off circulation - which should be constantly monitored). Nor do I believe that an ADS is comparable to what that tribe has probably done.
First off, they’re a primitive tribe out in the jungle. I’m sure they don’t have clocks, I’m sure they don’t hang in 15-20 minute sets. It’s unlikely that their “weights” (read: “rocks”) are uniform. They probably hang using a “noose” type of connection (unless Bib has smuggled some hangers to them).
Nor do I believe they would be as concerned with discoloration or temperature (how cold could their glans become in Africa?). In a village where life is threatened daily with war, wild animals, bacteria (a scratch could lead to death in the hot, humid climates - removed from antibiotics). I just have an image of a tough people, struggling to survive. They probably know nothing about circulation, necrosis, etc. It’s probably all trial and error, and “machismo.”
If this tribe does hang rocks, and if they are huge (i.e., did it a lot), it’s probably through their neglectful methods that they’ve damaged their penises. Also, I do believe there is an outer limit of safety for each of us (in terms of size, from where we started, etc.). Push the limits too far & I believe that damage occurs.
edit: One more thing….I’ll bet they walked around all day with those rocks dangling, swinging around, twisting their penises every which way. Even occasionally getting snagged on things. They probably went through their busy daily struggles with the rock swinging away (increasing chances of injury/damage). Only we in the West could even think of sitting on our asses for so much of each day - whether we’re hanging, sitting at a computer terminal, office desk, or behind the wheel of a commercial vehicle.