"You did not just boop me." Arthur says, stunned before taking a step back to look up at Lars, who looks back with an amused smirk of sorts.
"Yes, I did," He raises a gloved hand up teasingly "Sometimes you need to learn how to be quiet."
"Be quiet? Whatever do you mean?" Arthur blinks, pushing the raised hand back cautiously.
"You just went on a whole rant about how you despised Alfred's behaviour despite being a proud big brother for around an hour," Lars points out, getting another boop on his nose in return "What was that for?"
"To get you back."
"Hmph. Fine." The Dutch man huffs before the two of them engage in a war of sorts trying to boop the other's nose. Which ends in two bloody noses and lots of laughter.