Your poor sub loves holding so much that instead of needing encouragement to hold it, they need encouragement not to.
It's the day after a big, big hold and their muscles are weak and aching. If they hold again today, they might really hurt their muscles or give themselves a UTI. You know sub would never choose to give their bladder a break, so you take the initiative and put them on a strict schedule for the entire day: they must drink any water you offer them, and they must empty their bladder at the top of every hour. It's easy, but for your sub it's torture. They whine through every second of it.
At first they're whining because it's not fair-- what do you mean, I've gotta potty again? I just made a potty, I don't have any more!-- but you won't hear it. After making sure they're sufficiently hydrated, you sit them down and make sure they empty, even if it's only a few drops. But as the day goes on their body is getting more and more used to cycling this amount of water and they accept their fate with little whining noises at the back of their throat as the drops become dribbles become short, gentle streams. Toward the end of the day you silently decide they need a reward for good behavior: you make them drink double what they've been keeping up with so far, and you make them/offer them their favorite caffeinated beverage. If sub recognizes what you're doing, they don't let on. They drink every last drop.
You can tell that the drinks go straight through them, even if sub is trying desperately to contain their tells. In fifteen minutes, their hips are doing tiny little shifts in their seat and ten minutes after that you catch them bouncing a leg. You estimate that they're around a 5 or 6/10. It's time to empty again.
You take them back to the bathroom and they're desperate to convince you that they don't have anything in their bladder. "It's not even the top of the hour yet," "I JUST pottied I'm completely empty," "nonono pleasepleaseplease," but you make them sit anyway. They wiggle desperately on the seat as an act of defiance, willing their tired muscles not to release a drop. "See, there's nothing in there! I'm trying but there's nothing in me!" It's incredibly unconvincing, and they know it. You just cross your arms and stare at them in silence as they shift uncomfortably under your gaze. You haven't offered any punishments, rewards, or ultimatums, but you don't have to: sub is already weighing the options in their head. It doesn't take long for them to decide. They meet your gaze and then look down in defeat.
"Sorry," they mutter, and finally a healthy stream of a mostly-full bladder tinkles into the water beneath them.
They're so disappointed to be relieved.
