
So for this mega festish creature to realistically exist (take my words how ever you wont) they would need a couple things changed 

Genetics/Body
1.The Selaiki body type will have to be Dominat in the genetic code with males being the same probably a bit fatter but that's it.

2. The fat Glutius maximus must be around 40-50 lb since its the most plausible way a human with a large ass would every exist its essential just making a human camel but all the fat is in the butt.

3. The Skeletal structure must be at more dense or just better built to carry that much weight with the pelvis probably becomijg bigger as well, another things is that the muscles will probably be stronger as well (alot of muscle in the legs).

4. The gender ratio would be 50:50


Social structure & location 
1.For the location the population would need ot be isolated so central Asia and the north part of south Asia will do with the most common areas were you could probably find them being in valleys, or area with geothermal activity so they can farm probably in a mountain.

2. The hole race would be a matriarchy no doubt about it mostly because with the fat there able to survive longer this would turn into essential a hyenas social structure where the femals are at the top and the males are at the bottom but its more equal.

3. With the matriarchy like 10% of men will be used for breeding but to make sure incest don't happen men that came from trade caravans from the silk road would occasionally get kidnapped and be used as breeding tools.

4.Culturally being fat or chubby for this group would essential be a positive thing so I'd you a big guy a Selaiki would probably want kids.


**Note: dont take my words for biologically realistic Selaiki this is what im saying is plausible also they would have ti be a human phenotype**

Realistic Selaiki