This got away from me tbh. I'm not even 100% sure on what my Lucy is like but here you go, with one of my new OCs Lucretia!
It was inevitable that even the best behaved Weasley child would end up in detention. Lucy doesn't get into nearly as much bother as her cousins (and sister) but there's no reason Professor Longbottom should be so surprised - besides, she was only defending herself from bloody Lucretia Selwyn. She'd said Lucy only got on the Hufflepuff Quidditch team because a) her family and b) the team was desperate.
Uncle Neville (because she called him that in defiance, to which Lucretia sniggered) had asked if she needed to respond by throwing her treacle at Lucretia. Probably not, but no one insulted her family and house.
Then Uncle Neville had asked if Lucretia needed to stand on the benches, to which the girl had crossed her arms and nodded solemnly. "Lucy's taller than me, sir - sorry, Uncle Neville - so I needed a tactical advantage. Not that your house would know about that, Weasley, seeing as Gryffindor are going to crush Hufflepuff next weekend."
"At gobstones, maybe," Lucy remarked, looking away from the other as if she had no time for her. The glare Lucretia could have scared Voldemort himself, probably.
"Girls," Uncle Neville sighed in a tone only a father could achieve - as if on cue, Professor Patil knocked on the door and told Uncle Neville that his son Ieuan had been in a fight with Hayden Eastwood and when Albus (one of her cousins) tried to break them up Ieuan accidentally punched him.
"Brilliant," Uncle Neville muttered, apparently forgetting Lucy and Lucretia were in the room. "He's been off the bloody rails since Hannah and I seperated," he was talking to Professor Patil now but Lucy just glanced at Lucretia, who looked equally uncomfortable.
Professor Patil smiled sympathetically at him. "Don't worry, Victoire will patch him up." (Another of her cousins.) "Oh, yes, girls. How long have they got left?" Uncle Neville said they had about twenty minutes (in fact they had almost an hour, bless him) and the professors made them swear not to kill each other while they're gone.
They sat in silence for a couple minutes. Eventually Lucretia said, "Ieuan has been getting into so many fights recently. He started having a go at Aurturo Dolovoh the other day 'cause he was walking too slow up the stairs - and Aurturo had just broken his leg playing Quidditch." Lucy nodded. She had heard about that too. "You'd know, being all chumy with his family, so is it true Professor Longbottom and his wife got a divorce 'cause he was having an affair?"
Lucy knew the whole story but did not think she ought to tell Lucretia Selwyn of all people. "Not really, technically they were already divorced when he started seeing someone." She definitely would not be saying he was seeing Victoire - mainly because Lucy wasn't meant to know that. Was it her fault the adults in her family couldn't whisper? "But you should really worry about your own family."
"Meaning?" Lucretia asked, face darkening. Lucy knew she'd gotten some trouble in the past for being the child of ex-Death Eaters - which Lucy didn't think was fair, and she was not Lucretia's biggest fan.
"Don't get so defensive, Merlin. No wonder you're a Gryffindor. I only meant your cousin Paris is going out with my sister Molly and I really don't approve." Paris was a beater on the Slytherin Quidditch team and had an obnoxious laugh but Lucy didn't think he had a personality beyond that. Molly wasn't the best with boys but this one was a mistake.
Clearly, that surprised Lucretia. "Really? Neither do I. Actually - and don't you dare go telling anyone or I will hex you into next week - but I think Paris is cheating on her. Sorry," Lucretia added awkwardly, and she sounded genuine.
Lucy raged silently - which meant she was so angry she couldn't even shout. How dare Paris bloody Selwyn think he can mess her sister, her silly, wonderful sister, about like that. And how did he even get more than one girlfriend?
Slowly, Lucretia slid off the desk she had been sitting on. "You know, I need to get back at Paris for some homophobic comments he made about me. As his dear cousin, I know where to hit him where it hurts. If you want…"
It was a question; a request, even, to put aside their grudges and fight a common enemy. Between Lucy's sneaky tactics and Lucretia's brute force, a gross teenage boy was nothing. "Yes, I'd love it." They both grinned and sneaked out of the classroom, past the patrolling prefects, into an abandoned classroom where they started hatching their plan. This wasn't a friendship, not really, but an alliance of sorts. (They'd finish their food fight later.)