Excellent points made so far!
Timing so that it happens in your sleep: oh, you poor thing, nightly ruined finishes, making a mess in your panties? Or worse, you get jolted out of sleep for it exactly too late to prevent it or enjoy yourself! How sad 🤭
Timing it intentionally to set yourself up for fun: maybe try to aim for mid-play session with a friend! Or so that you're positioned for maximum humiliation, trying not to make a peep in public.
No impact on libido: maybe you think you're in the clear with a low libido, but, oops! You slipped up again because you so rarely think about jerking off, and now you're cumming handsfree, confused for a split second before the rushing dread of inevitability that feels better every time...
Slightly off 24hr timer: how much of a nightmare would 20 or 16 hours be? One slip up and suddenly you realize with sinking terror, doing mental math in the middle of a work meeting, realizing you're seconds away from embarrassing yourself unless you can hide your tells!
Eroticize that general forgetfulness: well, I love a confused little pet! Did you forget to get off earlier and now you're paying the price? I'll just enjoy the show while I tease you for being so needy and easy as you whine in embarrassment! Maybe I'll force another finish out of you right after, too, just for fun 🥰