AU where Baelor can't squeeze himself into Valarr's armour; no matter how hard he tries, he can't get head into the helmet, the breastplate doesn't sit right in his shoulders, and the chainmail is too tight around his chest, stomach, and arse. And he hasn't even tried on the leg parts yet!
Thankfully (sorta) Valarr walks in at this point, asks his father what the fuck he's doing, and proceeds to bitch at him about the whole thing, (Wtf are you doing, always so chivalrous and dramatic, is the hedge knight really so pretty that you've lost your fucking senses, right get out of my armour, I'll handle this) and takes the armour off of his father and puts it on himself.
Finally! A chance to prove himself before the realm and to punch his least favourite cousin in the face! Valarr could not be more thrilled!
Baelor on the other hand is not ok! His son is in danger, he has body image issues now (he is taller, broader, and more muscular than Valarr, which is the main reason it didn't fit, but he's fixating a little in his tummy and arse not fitting), and he doesn't get to ride out and save his the hedge knight. Not a good start to the day!
So Valarr rides out to join Dunk, and Maekar rides after him, already shouting about what the fuck is Valarr doing and does Baelor know his son is being an idiot, and trying to scruff Valarr to drag him out of the field. Only for Valarr to announce that if his father could fit into his armour, they would have had to have had a fight about who got to join sir Duncan's side. And look, there his father is now, standing with sir Duncan's team with the last pieces of Valarr's armour and arms. Maekar is pissed and Dunk has major heart eyes!
Baelor serves as Valarr's squire to visually show his support in front of the lords and smallfolk, but also so he can fuss about Valarr and Dunk. He gives the same sort of speech, recommending that Valarr could use himself as a distraction for the kingsgaurd (advice Valarr immediately ignores, his plan is to do as much damage as physically possible to the other side. It's his time to shine!). He hands Valarr his war lance, and squeezes Dunk's knee and offers them both advice about staying on their horses and specific weaknesses he knows about the kingsgaurd and Maekar's fighting style, because his baby is in danger! And his the hedge knight! And he can't do anything because he didn't bring his fucking armour! (Last time he makes a stupid decision like that!)
Ok that's all I've got for now, just, Baelor can't fit into Valarr's armour and has to let Valarr fight for him. I am leaving thoughts on the tags until I think about it more