“I may be on the side of the angels,but don’t think for one second that I am one of them.”

• Dean accidentally called the mandrakes, mandarins and the name has been a long running joke since then.
• Cas took a particular shining to Herbology, so one summer, he took home one of the said ‘mandarins’ and got kicked out of his house for a week so he brings them to Dean’s house and everyone hates him.
• Chuck wrote the Harry Potter books, so now when someone starts a conversation about them with him he just gets up and leaves.
• Dean brings mobile phones with him so he and Cas can contact each other at night.
• Everyone has a crush on Cas and he’s completely oblivious and Dean gets a little bit jealous.
• Dean tells Cas all about the muggle world, and Cas helps Dean enchant some of his comics so the pictures move!
• After being introduced to comics, Cas finds out his favourite character is Poison Ivy.
• Crowley put itching powder in Dean’s trousers which results in him running into the lake and asking Cas to get him clothes.
• Dean gets banned from going to the Yule Ball, but he sneaks out near the end of the night and goes to have a dance with Cas (probably wearing his pyjamas)
• Dean figured out how to get into the Ravenclaw common room, so when Sam comes along, he, Sam, and Cas all sleep around the fireplace together.
• Cas also knows the passwords to the Gryffindor common room and sneaks up to comfort Dean.
• Sam and Dean go swimming in the lake in the late autumn and Cas stands at the side, complaining about how they’re going to get sick
• They get sick and Cas stands there smugly like ‘I told you so.’
• Sam somehow figures out an enchantment for internet wherever he goes.
• Near the end of their time at Hogwarts, Dean manages to sneak in some firewhisky and he and all their close friends have a little party at the lake 
• Sam had crushes on everyone, including Cas - who he gave a little bee pin to.

• Sam is a first year with Jo, Brady, Hannah, and Ruby when Dean is a second year with Cassie, Bela, Amelia and Jess--cos he purposefully got held back, Castiel’s a third year with Meg, Uriel, Balthazar, and Crowley, Anna’s a fourth year. Lilith, Azazel, Alastair, and Zachariah are fifth years. Lucifer’s a sixth year, with Naomi, Michael, Raphael, and Gabriel.
• (Slytherin!/Gryffindor!) Sam uses his connections in Slytherin House, while (Hufflepuff/Slytherin)Cas is already planning something, and they both get tangled up in vengeful acts against Crowley’s itching powder that get them detention; Sam’s was even harsher than Castiel’s but Castiel does put Crowley in the hospital wing once he learned he just wanted Dean to get naked in public, and he’s not sorry; Crowley should know better than to sexually harass his boyfriend.
• Cas, like Draco or Sirius/Regulus, starts out being used as a weapon against people and gets dragged back into his family’s faction of Slytherin and Gryffindor over and over again, but they keep trying to hurt people, especially Gryffindors or Hufflepuffs, which he’s not into, so he ends up foiling their plans more often than not and hiding in Dean’s dorm/at Dean’s house so they can’t find him to punish for it.
• Cas may laugh at Sam and Dean for a moment when they get sick but he also persuades (Gryffindor/)Slytherin!Meg, the Healer apprentice crushing on him (who mostly got into Healing to learn all the ways to kill someone or find vulnerable people to join her crew, and actually finds sick or disabled people very irritating) to give him some Pepper-Up Potion and whatever else so they’ll recover faster.
• The bee pin (sex-indifferent straight) Sam gives Castiel isn’t a “crush” thing but a gift as friends (which has nothing to do with maybe getting Cas to persuade Dean to stop doing 'for the Vine’ stuff like spelling [Hufflepuff/]Ravenclaw!Jess’s notes to read ‘Mrs. Jessica Winchester’, stop looking at him like that, Cas, he promises!).
• It took Cas and Sam two years to successfully spell parts of Hogwarts to allow electronics but the ambitious shits had to have it done by Dean’s birthday on his sixth year so they could listen to his music at his 16th birthday party.
• Castiel mostly tries (and y’know, plants and bees--doesn’t always succeed) to stay out of the hospital wing because of that one time the Healer apprentice, (his Housemate? Only if Slytherin.) Meg, tried to slip love potion into his cup of Skele-Gro; he’s aware of her crush after that and warily squishes closer to Dean or Ruby whenever she looks at him following that incident (but still steps in front of a hex for her that one time, cos he owes her for the Pepper-Up).
• Because yep, everyone has crushes on Castiel, and Dean is jealous a lot, but Castiel eases him as soon as he realizes what’s going on, because Castiel is a sex-indifferent greyromantic demipansexual who wants no one but him. (”I’ll be with you forever, Dean. I may not hate them, they may even be my friends, but you’re the priority.” and lots of kisses.)
• If Sam hadn’t figured it out Dean would probably have gone to Azkaban for the reckless spells he threatened after Team Free Will stopped Meg. It’s one of the only times Sam saw Dean admitting to wishing he knew more Dark Arts, the stubborn “some magic isn’t good, don’t use that” ass.
• It’s not as though Castiel doesn’t have tons to be jealous about when it comes to Dean, either. (Ravenclaw/Slytherin)Bela Talbot is hardcore into Dean--he thinks her butt is hot but her morals repulse him, and Prefect (Ravenclaw/Gryffindor)Cassie Robinson still pines for him, and Quidditch Captain (Slytherin/Hufflepuff)Lisa Braeden is one of the “hottest weekends he’s ever had”. (Whenever Castiel starts getting jealous, he drags him to his dorm and kisses the daylights out of him and whispers, “None of them ever saw this place, or my house, Cas. We’re gonna last.”)
• (Slytherin/Hufflepuff) Ruby has a crush on Sam even after he dumped her during her dark days and a deep, abiding friendship with Castiel formed at first by grudging allyship out of wariness of Meg and her crew, after Ruby’s graduating Evil Slytherin friends turned on her when she refused to hurt Sam or someone he loves for any reason, because Meg’s people took over for them when they left. They’re both part of the Herbology club.
• Ruby is how Sam figures out what Meg was going to do to Castiel, and Sam grudgingly forgives her when he refuses to believe her at first and she breaks down in tears apologizing to him; thinks it’s a ploy for a while, though, til she kisses Castiel’s older sister (Gryffindor/Ravenclaw) Anna (who banged Dean before Dean realized he wanted Cas; who someday wants to teach Defense Against the Dark Arts at Hogwarts or something similar at Beauxbatons) in front of him.
• Ruby and Dean don’t see eye-to-eye; she thinks he’s too careless and stubborn and he thinks she’s always going to turn into another Lilith.
• He gets over some of that later when Cas, lying on his stomach in the Gryffindor dorm, points out Cas and Ruby aren’t that different, and he loves Cas, doesn’t he? Give her a chance?
• Ruby and Jess become friends after they have this huge blowout over hurting Sam when Lilith leaves.
• Jess is a year above Sam and knows Sam is into her because Ruby and Dean never stop talking about it, but she’s busy right now; she kisses Sam at the Yule Ball and says “Look me up when we’ve both graduated.” 
• Castiel is the only one Jess tells about being into Sam too, and he tells no one, not even Dean, but just quietly waits for things to work out. She trusted him, after all.
• Sam’s sex life is somewhat prolific (though nothing on Dean) but his love life so far only consists of a Gryffindor/Ravenclaw student in Jess’s year named Amelia, then go back further to Ruby and that mess, then go back further to the jones he’s had for Jess since the Sorting ceremony (and man, he was bummed when they didn’t put him in Ravenclaw with her--provided they didn’t).
• (Sam asserts that having a crush on and/or ‘doing stuff’ with a werewolf, Madison, didn’t count. He’s on the fence about Amy. Both first years in his second.)
• Castiel at one point is in a club with Housemate Slytherin!Crowley but when Crowley is about to become the leader, he and Meg temporarily align to disband the club (though Meg really would rather replace him) so Crowley doesn’t get that much power, but then she sexually assaults him (again) and he’s reminded that friendship is impossible.
• Dean and Sam have hated Meg ever since she took over when Lilith left, but they don’t like her rival, Crowley, who has a lot more Hufflepuffs and Ravenclaws behind him, any better.
• When Crowley, Meg, and Castiel graduate (in the same year), Meg and Crowley end up in Azkaban for the ways they try to one-up each other and Castiel visits them both exactly once (and tries to tune out Dean’s gloating over it--it’s harder over text, so he mostly just responds with -_- emoticons until Dean stops doing it).
• Dean gets detention in seventh year every other weekend for sneaking Castiel into the dorms after he graduates; Castiel kisses his forehead and says something fond and exasperated about how he’ll never learn.
• Dean never does learn, until he graduates and becomes an Auror apprentice while quietly developing magic-impervious electronics in his spare time. Castiel, the indecisive-but-ambitious trust fund child he moves in with after graduation, is the only one who knows how passionate he is about it, until he ends up quitting the Aurors years later (while Sam, surprisingly, stays, as long as he’s a higher-up with less field work, with his recently graduated Slytherin/Ravenclaw apprentice Kevin) and opening up a shop in Diagon Alley (to much uproar, with his more recently graduated Hufflepuff/Gryffindor friend Charlie) to sell them.