ooo thank you this is a really interesting question! when i write childe in canonverse i'm usually writing him as gay- this ties in with a few other headcanons i have about him spending his adolescence as a fatui soldier, and the type of sexual awakening he likely had in that environment, but i think he definitely also carries some delicious religious guilt about his sexuality that caused him to try a few times to straighten himself out (see my previous answer about him and skirk, signora, the tsaritsa...hehe). i feel like his obsession with constantly talking about, and projecting an image of, his perfect family is also really interesting if you view it in that context...and like, not to get too meta about it, but you wouldn't have to stretch (heh) too far to see the metaphor in childe falling into a gaping hole as a child and coming out different.

bennett i tend to write as much more freewheeling in both canon and AU, like, i really don't think he thinks about this kind of stuff at all. i think he could be attracted to any type of person, and down to try having any kind of sex. i think he just fundamentally does not understand childe's various neuroses around this topic at all LOL...for how lacking this half of the answer is i will throw in a depressing hc for free: i think he prefers to bottom because if his luck causes anything to go wrong, then he'll be the one bearing the brunt of the pain instead of his partner