I have a few things along a similar theme that I don't really understand why they're unpopular but no one else seems to really vibe with them.
One scenario that I imagine writing a story about at some point is a baby who's a lot physically stronger and a potential danger to their caregiver. Like, I'm imagining a huge, buff bodybuilder type of guy with the mind of an infant. He has this super-hot, young, babysitter type who is his regular caretaker. He's crazy strong and so the dynamic is such that she has to be super placating and loving towards him in order to do anything. Like he needs a poopy diaper change but he's too busy playing? She has to be really placating and careful about getting him to agree to a diaper change, because if he throws a tantrum it could be pretty dangerous and he could hurt her. She keeps up with the role though specifically because she can't help but violently lust after him though. So even though she has to care for a baby that's physically bigger than her and could easily throw her across the room, she still wants the opportunity to ocasionally sit on that dick, and that also becomes another way in which she placates him, once he learns that the babysitter isn't just there to change his diapers and feed him, but to help him make big cummies in her small little body too.
A couple other scenarios that involve very specific vibes would be like me having a Mommy, or preferably multiple Mommies, who are all trying very hard to please me, make sure I'm babied and taken care of, and basically never have to do anything. To the point where they're actually phsyically fighting and competing over who gets to carry me, bathe me, change me, jerk me off, etc. It's important though that although they all really want me this way, and are adamantly competing over me, they're still grossed out by my diaper changes. Like after literally winning a contest of some kind for the right to change my diaper, the winning 'Mommy' is still obviously grossed out by my poopy diaper despite being honored and grateful to change me.
A variation of that is I love the idea of a super haggard, worn out ABDL fantasy Mommy. I'm imagining a household where it's one ABDL super-Mommy who's really tall, super busty and beautiful, and dressed like a 1950s housewife all the time, maybe even with a diaper-apron like what's referenced above:
>>25674
But it's just here taking care of a household of like 4 or 5 adult babies. I'm imagining like 3 female and 2 male. She's maybe a little taller and bigger than her charges but everyone is still within the range of normal adult humans. Basically, her whole life revolves around diaper changes. All of her adult babies are constantly pooping and peeing to a cartoonish degree. Like fully filling a diaper every time. The whole house smells like a nursery. The diaper pails are always full. The babies are also always masturbating or having sex with each other which she halfheartedly tries to discourage but knows that she can't keep up with all of them and figures it's better they get some relief that way rather than her trying to have to jerk them off multiple times a day during diaper changes. She loves her babies and wants to take care of them, but she is burnt out and grossed out by the constant diaper changes and caretaking.
Something like trying to take all of them to grandma's house for Thanksgiving means first changing them all into extra-thick diapers (since all that rich Thanksgiving food is probably going to make them mess themselves), then packing multiple diaper bags. Then she has to load each of these five adult sized babies into carseats for the ride over there. Then even though she just changed them, and even though it's only a 30 minute car ride, she knows there's still a possibility one of them could have a blowout on the ride over there. Which wouldn't bother the other babies at all, but she would be dealing with the dirty diaper smell the rest of the way.
The other thing kinda along these lines is what I think of as the 'Baby Herman' archetype.
If you've ever seen the movie 'Who Framed Roger Rabbit' Baby Herman is portrayed as a physical baby who has all the needs of a baby, but who's still horny, misogynistic and has adult girlfriends. It's vaguely implied that he's dating attractive, adult, human women who also change his diapers and have sex with him, while he's blatantly sexual and demeaning to them. Slapping their asses, looking up women's skirts, etc. Why isn't that more of an archetype in ABDL? That sounds exactly like how I feel. There's a few diapergirls on twitter who make it part of their persona to be blatantly sexual and slutty while still wearing diapers and acting babyish, but there's never a male equivalent of the same thing. My dream would be to be like a Hugh Hefner porn mogul, where I have women around me all the time, but I'm also just shamelessly in a diaper while I'm demanding things from them.