Curate, connect, and discover
I don't think I've read a single fic where Alastor and Lucifer get together because they make each other laugh. I need to see them being cringey old-ass qpr pals with combined -1000 rizz somehow charming the other by having horrible taste in humor.
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No one remembers who started it but hardly a day can go by without Alastor and Lucifer trading dad jokes back and forth like a hot potato.
As soon as one catches sight of the other BOOM cringe-ass pun and without fail the other will burst into uncontrollable laughter.
And the jokes are bad. Like really bad. Not even Charlie can find the silver-lining (and she has tried). Listening to them laugh at those truly horrible jokes sparks an avalanche of second-hand embarrassment on the part of everyone within ear shot.
It eventually gets to the point that just looking at each other triggers a Pavlovian response where they just giggle and wheeze before the other can even tell a joke.
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Someone: Really? You want to be with that guy?
Alastor or Lucifer: He makes me laugh :)