i am also still thinking about it... (tw dubcon?)
and that's exactly the thing!! it starts out erotic - you get to switch off a little, experience the day without having to think about anything, any of the micro decisions and asmo can take care of you/your body however he sees fit. he can play dress up and play pretend, see what it's like to be you. you go in thinking it's a bit of an experiment with a caregiving dynamic, and he puts you so at ease promising that he'll take such good care of you, that he won't do anything too outlandish, that you can pull the plug at any point but then 6 hrs turns into a full day of possession before he relents and gives you your autonomy back.
but you've opened the gate now and any opportunity your guard is down he's possessing you, playing at being you. he starts coercing you into it before ultimately he just stops asking for your consent and suddenly your backseat driving in your own body, feeling distant and floaty and not in the pleasant way it originally was.
there's a creeping, foggy unease but you're not sure what it's about, because asmo is in control more often than you are now and you can't quite work out what's wrong, where you start and asmo ends, if asmo is even pretending to be you any more or if he's claimed your body as his own vessel. he uses glamours to change your height, your weight, your hair colour and style like your own body is his doll. it's horrifying to be lucid in those moments, watching the mirror as he distorts your appearance for fun until he decides your original appearance is his favourite.
you forget what your own convictions and thoughts even are because it's been so long since you've been alone in your head. and no one notices. the change is so gradual and asmo is such a good actor at the start that they just assume it's you being influenced by them, growing and changing in the way humans do.
you try to get their help asking solomon about exorcisms, how pacts factor into possession and he just laughs you off, saying its not something you'd need to worry about after all who would mess with you, with the strongest demons at your beck and call? except said demons of course.
even when asmo gives you back control for shorter and shorter periods, his voice is still whispering in your mind that it's easier just to let him do it, let him make all the decisions that your fragile mind avoids, let him look after you, why do you need a sense of self when he's been doing so well taking care of you? remember that this was enjoyable at the start...