What if Kara slowly introduces Lena to more informal side of life so she gets to do many things she had been taught all her life not to do bc she's a Luthor.. stuff like drinking beer straight from the bottle, putting feet on table etc
You know Lena thinks it so weird the first time she goes to game night and everyone just kind of half sits on couch, half on the floor and eats takeout all around the coffee table. And Kara hands her a plastic fork? and this is most definitely not a wine glass, but it has wine in it?
And the first time Kara builds them a pillow fort in front of the tv is an experience to be sure! And Kara gets so excited every time Lena experiences something new!
Bonus HC- one time they all convince Lena that some weird thing is what ‘regular people’ do. and so she finally does it and they all die laughing because they can’t believe she actually did it. She wants to be mad, but she’s honestly never felt so included? because instead of her Luthor upbringing being an obstacle they all just tease her about it and she’s never really had friends close enough to tease her about anything so she wears it like a badge of honor!