YOU HAVE NO IDEA... I have a solid idea that Wriothesley would have a very big bone for gift-giving in terms of trying to get Childe to accept gifts to supply to his siblings probably just as much as he tries to spoil them.. oh them and their need to care for kids. But Wriothesley would attempt to do things a bit more hands-on, like make mechanical gifts himself. But it's been so long since he'd worked with mechanics so he'd probably be a bit self-conscious about it but Childe would dismiss that and accept the gifts without even a moment of hesitance, almost beyond excited to hand off the gift to his siblings in his honor.

I also think about how they would possibly nag one another for their bad habits, from the simplest ones to the heavier harmful coping mechanisms. As is the nature of self-appointed caretakers they'll simply butt heads until they reach a stalemate, realizing they'll probably never be able to get one another to quit their bad habits but at least they can comfort one another in times of need. Most of the time when you're feeling as indescribable as ever, all you need is a warm body to lean back on.

A sillier one, Wriothesley has accidentally drank moldy or expired Tea more than enough times. And I imagine that Childe would find that gross and unsanitary, even ending up in situations where he would purposely lean across the desk to check and make sure the Duke is not sipping from a cup of moldy tea. And when he is? Wriothesley has a pension so stare him dead in the eyes and down the glass like a total freak. He's a hypocrite truly, ragging on Sigewinnes milkshakes only to turn around and down a glass of moldy tea just to get on the nerves of a Harbinger who takes housecleaning and hygiene very seriously.

Perhaps I will have more to share in terms of HCs in the future but right now I NEED TO TAKE MY TATERTOTS OUT OF THE AIRFRYER.