Ahh my fave Stark siblings!! I definitely have a few:
The most embarrassing dancers. Will be vogueing on the dance floor and doing the robot to a pop song.
Have done every challenge meme there is (they DEFINITELY pulled the others into doing the Harlem Shake).
Sansa definitely pulled Robb into doing tea parties with her when she was really little. She’d pour real tea into his cup (thankfully Cat made the tea and not 5 year old Sansa) and tiny little cut up lemon cakes.
Robb would sit around with Sansa’s 10 stuffed animals, fake talking to them and drinking their tea too.
At some point they started doing a code thing for bad dates??? Robb started it for Sansa so that if she hated a date she’d just text him “limes” and he’d know to call her or come into the date “accidentally” and interrupt - but as time went on Robb had quite a few dates that went poorly and Sansa had to bail him out of it.
Her best bailout was definitely when Robb was on an awful date with a duchess and Sansa dramatically walked through the doors yelling, “ROBB, ROBB YOU haaaaAAAAVE to come QUICKLY! Our stAAAAAAABLE, it’s on FIRE! Our horses are gone, our livelihood, our PRIZE WINNING SHOW PONIES!”
She continued yelling dramatically and pulling him up out the restaurant and wailing until they walked through the door and said, “So, bad date?”
Robb’s best bailout was when he walked in on a cafe date, said, “You’re insufferable, leave,” and promptly kicked out an incredibly offended Joffrey and ate his dessert.
Both have a major crush on Dua Lipa. There’s no other headcanon there they just do.