Casval, while on the deep space exploration vessel made by yours truly, has to constantly put up with the ship's AI system, COS (Central Operating System). One of COS's goals is to ensure Casval has good physical health. And by that, it means making sure he doesn't get rashes. So every now and then, he has one of his mechanical arms pull out the back of Casval's diaper to check it, something Casval still hasn't gotten used to.