perhaps this is not that hot of a take, but i really enjoy the idea of my partner pissing themself. im not really into piss, but the desperation aspect that comes along with being made to hold it is undeniably hot to me. like
"you wanna be oh-so-very-good for me, right? drink. you need your hydration, my love. keep going, honey, you're doing so well."
id let some time pass, keeping a close watch on their behavior and continuing to coax them into drinking more water.
"something wrong? you're starting to squirm, sweetheart... you have to pee? aw, my poor little thing! you can hold out for me a little longer, though, right baby? mhm, good pup, have some more water for sir, okay? you can do it, baby, make it fit"
when they finally can't hold it any longer, can no longer sit still, when they're whining and begging to be let to go piss and their hearbeat has gone erratic, then and only then would i give permission
"you need to go, honeybun? alright, baby, go ahead. no, you can't get up from my lap. if you need it that bad, surely you won't make it to the bathroom anyhow, right? better to go right here where we can clean it up nice n easy, yeah? that's my good pup, let it all out <3"