the demons in my worldbuilding are very flirty. Extremely Flirty. a lot of their cultures focus a Lot about sexuality (and economically speaking, it is very much capitalised on). it is considered standard practise to flirt and tease each other in regular conversations and not doing so isn't considered rude per se, but instead Overly Formal to the point of it being seen as ridiculous. of course, not every demon is flirty (i have several OCs that aren't), though there is definitely a pressure to, which isnt helped by the fact that most demons don't wear clothes...
in addition, it is common for demons to have a Special Type of Relationship which i like to call the Quasi-Romantic Friends with Benefits Sorta Thing. romance isnt really as Big of a thing as sexuality is for demons (it does exist but its just not focused on as much) so there is a tendency to have a combination of romantic, sexual, and platonic attraction between people. this relationship May turn into something more romantic but its common for it to stay like this for years (especially considering how long demons live)