#Right up until he picks the handcuffs or explodes the cage bars or tricks a minion into giving him the keys

[tswwwit]

Kidnapping being a common way to confess your love in the supernatural world and dipper getting kidnapped while he was just trying to do research in the fearamid library (it has a lot of useful books in there, although surface level information but most of it doesn't exist back in the overworld, and demons barely use it, the demons that do use it really just wants to gain knowledge or read) and then the world goes black and he wakes up clearly still in the fearamid (because he sees that same horrible wallpaper in the background he usually sees in guest rooms) only to see like a mid ranking demon serenading him, he cringes because not only does it have bad singing skills but he doesn't want to see anyone explode right now (who evens kidnap someone and deposit them in the same building? This probably isn't even it's room because only higher ranking demons get guest rooms)

(Sorry for word vomiting

bleeerrghhhghggrh.... hlehrghehehg

Wipes mouth and sorry for vomiting)

(Also sorry for using a lot of these cage thingies)

The funny thing is, kidnapping Dipper and staying in the Fearamid while doing it is like. One of the few ways not to have Bill notice immediately and twig to something being wrong. What with Dipper still Being Around Nearby, and if he isn't responding to Bill's calls or texts or anything, hey! Maybe he's just being huffy about something, he'll calm down soon enough.

Obviously the demon in question didn't think that far ahead, and is in for a very very bad time in short order. Dipper, meanwhile, is likely an old hand at the kidnapping thing at this point to be so blase about it.