My personal Heated Rivalry headcanon is that David knits and Shane would constantly go around wearing the ugliest coziest Weasley style sweaters when he was younger.
Ilya finds out that David knits and it only adds to his teasing of Shane’s boring genetics and any time he gets to see a picture of toddler Shane in the ugliest sweater known to man he ribs and teases him without fail but makes sure Shane knows just how cute he is wearing them, asking why he doesn’t have any as an adult.
One Christmas Shane gets a knitted jumper (slightly less ugly than the childhood ones but still not the most fashion forward) and Ilya gets so geeked about it bc yay he gets to see his baby look like a baby again!!! Only to then be reduced to absolute body wracking sobs when he opens his present and it’s a matching handknit sweater from David.
