He thinks on it for a bit, before making a decision. "Hmmm... How about keeping it simple." He starts getting to work, typing out the changes he wants.
"In this world, everyone with an older sibling will live inside of the sibling directly before them. In the case of twins, this is decided by the order they come out. Those of age can still move out, thus having those spread out into different houses; Anyone living inside will move as well."
"The oldest sibling will live in the house with their parents, housing all other siblings inside of them. They can also choose and push someone out if needed; For example, if there are three siblings, and the youngest needs to come out, the oldest can push the middle child out, who can then push out the youngest."
"This is so those reliant on outside interaction, such as infants, aren't stuck inside and end up dying within. Anyone can, technically, enter anyone else; Those in a relationship can live inside the same person, for example. There is also no limit to how many layers of this exist; Someone with a hundred siblings can still hold the full hundred, with weight being the only limiting factor."
Jeff was mostly pleased with this, and went to hit confirm... but it didn't work, instead an error message showing up. "Error. Not all required fields are set." He looked back... realizing his mistake. "OH. How could I forget the body part!"