Hi I can't sleep so I made this (ngl I'm TERRIBLE at deciding things, especially because it totally depends on my mood, the au, the vibe, etc etc, so this can change literally in five minutes)
Ignore the fact that I forgot their height difference. I think they're pretty even until Keith's galra genes strike (he's not as tall as the other galra but he does gets taller than Matt)
I considered not including their age difference because it depends on which AU I'm talking about jansns but I feel 3 would be their canon difference (at least at the beginning of the series, then with all the space shit and everything... Idk man)
They don't usually sleep like big/small spoon, Matt sleeps sprawled out on the bed and Keith snuggles up to him. They always wake up tangled up
Ever since Keith's galra senses began to sharpen, he steals Matt's hoodies, sweaters and t-shirts all the time. He loves his smell
Matt LOVES using pet name. His go to are "baby" and "babe", but when he wants to be annoying, he uses horrible ones like "snookums" "boo" "love muffin" "sweet cheeks" and anything that comes to mind at the moment. Keith, on the other hand, never felt comfortable using them, and prefers to stick to names
I don't think any of them gave the confession much thought, like it happened so naturally they didn't have time to stress over it
As they both know how to pilot a space ship, I think they're both capable of driving a car (although Keith tends to use his motorcycle, only using the car for long distance trips)
Matt can't cook for shit 100%. Colleen tried to teach both him and Katie the basics, but it always ended up with something burnt, broken and/or disgusting. Keith knows how to cook simple dishes, but he's not a fan. At some point in their lives they took cooking classes; it was hard (and Matt almost got kicked out at leas three times) but they managed to at least be decent at it
They can't stop touching each other, wether it is holding hands, putting one hand on the hips, on the leg, on the arm, tangling their feet, anything
Matt has zero experience. He's always been focused on his studies, and being an awkward science nerd didn't help. Keith has some experience, but not with relationships exactly iykwim they're each other's first actual relationship
Keith is more... Territorial than jealous, and Matt's not a fan of people (and aliens) staring and fawning over his really hot boyfriend, and when he notices someone's intention to flirt with Keith (and since he can never tell if someone's flirting with him unless they say "hey I wanna sleep with you"), he just goes to them, puts his arm around his waist and kisses his cheek