If there was one thing Ladybug had learned about Chat Noir during their three years of partnership, it was that he never shied away from competition.
He was wonderful and loyal, of course, but he could also be terribly egocentric. Their friendship came along with a cycle of playful one-upmanship, and both parties constantly looked for ways to tease the other.
When they got bored during patrols, they'd race to the Eiffel Tower. Ladybug usually won. Sometimes they'd go to the park and fence with sticks. Chat was rarely defeated. After countless games, they concluded that they were even. That is, until recently.
Ladybug didn't know exactly when it happened, but Chat had shot up about six inches in the past few months. They'd been around the same height before, but his growth spurt made Chat a head taller than his Lady. Obviously, he used his newfound height as an opportunity to pick on her. During akuma attacks, he'd greet her with the classic, "How's the weather down there?" When she mentioned an upcoming family trip to an amusement park he asked, "Are you sure you'll be allowed on the rides?" By the time summer rolled around, her shoulders were in constant pain from being used as armrests.
She'd been waiting for the opportunity to get back at him, but never did she think that the stars would align so perfectly. Because oh mon dieu, this. This was priceless.
For a moment in the metro Chat had succumbed to his feline urges, letting himself purr in Ladybug's arms, and she was never going to let him live it down. He'd only purred for a few seconds, and he denied it so vehemently that it was useless arguing with him. Ladybug knew that she was left with only one choice: to do whatever she could to make him purr again.
(And this was not about her secretly enjoying him being defenseless and vulnerable putty in her hands, and she derived absolutely no enjoyment from having control over him, because doing so would require her to find him attractive. Which she did not.)