(Let’s do something when they were younger! I think it would be fun to go that route, haha.)
Ser Rodrick gave them wooden swords from the day they could toddle around; teaching them how to wield the sword, preparing them for steel, making sure they were ready in recent years to come. The pair of them picked up their wooden swords and pretended to be Knights, fighting on the Stairs, laughing over their missteps and words.
“Put down your steel now, and I promise you shall have a quick and painless death,” Robb called out. His quick steps in defense moved him forward, bringing the wooden sword to meet Jon’s, laughing when the swords crossed paths in a whack, both of them sliding across the floor from the heavyweight put behind it. His words were strained but filled with strength, hoping to strike fear into his brother.
They both parted, knowing that one of them would end up on their face; Robb whistled, amazed at how well his brother learned to wield the sword, knowing he started later than him. “Shall we try again?” He asked, his feet already getting into their fighting stance, waiting to lunge forward. Without a word, Robb slid forward, turning half-way, his sword out, ready to slice into pretending armor, only it caught on Jon’s breeches and pulled them down. Robb, let go of the wooden handle, surprised and finding humor in this situation. He burst out laughing, bending over, bracing his hand on his knees.
“I guess it is a good thing you’ll be wearing armor; otherwise, the only ballads that will be sung is not the swing of your sword but the other parts that swing.” He cracked, falling to the floor in tears, knowing that he would regret his words by the morrow.