By kamishiro_mai_(capti-no),sauce

by lansane,sauce

so, this leave a really big question for me… where is the…that part of the body located?

based on my experience on reading tons of doujinshi, I notice nearly all of them is located on the back. However, it also mean that the digestive system would be lengthen, thus, improving the nutrition recovery from the food, but requiring longer digestion time. It mean that they would have a higher food-to-energy ratio, rendering them a good choice for labor work.