When a character gets any kind of bodily excretion into their pants, such as pee, poop, cum, squirt, etcetera, they are made to stay in it for as long as possible. This includes something like diapers as well, so if a character uses their diaper they must stay in it for as long as they can. If the character being made to stay in their mess is submissive and they are under the control of a dominant character, then the submissive character will only change their clothes and/or diaper when the dominant character allows them to. Make sure to describe how the character(s) feel about sitting in the mess. How they do it don't like the feeling of being wet and/or messy, how they wish they could stay like that, or how they wish they could be done soon, how much the dominant character(s) likes seeing them in their mess, etcetera.