For reasons that continue to elude scientists, humans occasionally abandon their homes for a sleep cycle or two. This has especially been noted in young humans, but older ones have been known to do so as well. While a few theories have developed to explain the abandonment, none have been proven. Nothing has ever been discovered to be wrong with the homes and in fact there are usually humans that are left within the homes. Most often the humans do not travel far, sometimes only going within walking distance of their homes.

One theory stated that it was some sort of mating - or courting in the case of the children - ritual, as the humans take refuge inside the homes of friends and often sleep in the same room as said friend. However, it's been proven incorrect for the majority of the gatherings, though there were a few exceptions.

At this time, the most prominent - though heavily debated - theory is that it is a sort of social bonding exercise. Some believe it is a sign of trust from the invading party to the home's owner as they give up the safety and security of their own home to lie defenseless on the floor of the other's. Others believe it might be a show of strength on the invader's part for the same reason alongside the fact that those that fall asleep first occasionally find themselves the victims of vandalization or other mostly harmless attacks.

As it stands, Sleep-overs have been classified a great mystery of humankind.

- An excerpt from A Guide to Humans by Driniv of Xebnec 9

Allura yawned as she shuffled into the paladin's wing of the castle. She wanted to get to bed, but before she could, she needed to check that Hunk had finished up the work he'd been doing in the engine compartment.

When she reached the Yellow Paladin's door, she yawned again and pressed the access panel. To her surprise, the door slid open instead of sending a chime into the room to announce her presence. "Hunk?" she called, peeking into his room to see that it was empty.

That was odd. Was he still working?

The princess went a few rooms over, assuming that Pidge would would know where Hunk was, only to find the girl's room empty as well. She checked Lance's room, then Keith's next to it, but both proved just as paladin-less.

Finally she went to the end of the hall, half-expecting Shiro's room to be lacking as well. However, when the door opened, it was to the sight of all five paladins draped across the floor of the room amongst a mountain of blankets and pillows.

Brandishing a pillow, Pidge was sitting atop Lance's back in a shirt that had to be Shiro's, judging by the size, and a pair of sleeping shorts. Beneath her, Lance was wearing his usual sleeping clothes minus the robe and trying to knock her off with his own pillow. Hunk was off to the side, also in sleeping clothes with a bowl of edible seeds that he'd picked up from the last planet they'd been on. Shiro was wearing only a pair of sleeping pants and was leaning against his bed, watching the two roughhousing while combing his fingers through the hair of the sleeping half-galra on his lap. Keith was still in his usual clothes - though his boots were tossed off to the side - and curled up with his head tucked under Shiro's chin.

"Get off me you gremlin!" Lance shouted before getting smacked in the face.

"Make me, Tailor!"

"What are you all doing?" Allura asked.

The paladins, aside from Keith, all looked up.

"Oh, hey Allura," Hunk said. "Did you need something?"

"I… was coming to see if you had finished with the engines."

"Oh, yeah, everything's set."

"Right. What are you all doing in here?"

"We're having a sleepover," Lance said, suddenly lifting up on his hands and knees. As a result, Pidge fell off him with a yelp. "Ha! Victory!"

Pidge glared at him and he quickly scrambled away from her as she threw her pillow at him.

"Sleep… over?"

"You know, when you and your friends all sleep in the same room. Oh! We were going to invite you, but it was kind of a last minute thing-"

"My idea!" Lance cut in.

"- and we thought you and Coran had already went to bed," Hunk finished.

"Oh! Humans are a nesting species! You should have told us, we would have given you a proper room."

"Nesting species?" Shiro asked.

"Galra families and housemates all sleep in the same room. Children will sleep in the same bed as their parents until mid-adolescence. Galra don't sleep well separated from others."

The group turned to see a half-awake Keith peeking out at them. Shiro smiled and ruffled his hair. "Well, that certainly explains some things."

Keith huffed and smacked his arm.

"What things?" Pidge asked.

"Keith-"

"No," Keith groaned.

"- wouldn't sleep on his own until he was almost eleven, not without putting up a good fight. He used to try and sneak into my room all the time."

"That's adorable!" Lance laughed.

"Hate you."

Allura watched the interaction with mounting confusion. "So humans are not a nesting species?"

"No. Humans really only share beds when their, um, mates and children are normally discouraged from sleeping with their parents at a young age. Keith's just… stubborn."

"F-ou."

"And sharing bedrooms is normally only done if there's a lack of space."

"Then what's all this?"

The humans all frowned and shared a look. Eventually, Pidge shrugged. "It's kind of like… I don't want to share a room with these idiots every night, but sometimes we just… want to hang out until we physically can't stay awake anymore so we pile in one room and pass out there. I guess. I don't know, I've never had to explain a sleepover before," the girl growled, tossing her arms in the air.

The other humans all nodded.

"I see." She really didn't, but she'd learned it was best to just go with it. Honestly, this semi-nesting behavior, for lack of a better term, is far from the oddest thing about the paladins.

"So wanna join?"

"No, thank you." Sharing her room with the mice was one thing - they were mentally connected - sharing her room with a sentient lifeform that was not her romantic partner, let alone five, would be far too uncomfortable for her to fall asleep. "Goodnight."

"Night!"

As the princess left to return to her own room, Hunk turned to the Red Paladin. "So Galra Keith, you must love sleepovers then?"

…

"I think he fell back asleep," Shiro chuckled.

"I guess that answers your question," Pidge chuckled as well. "So Lance… You think Keith's adorable, huh?"

"I- wh- you- I didn't say that!"

A sleepy Keith is a cuddly Keith.

Galra bedrooms are just that, the room in a residence that contains all the beds. Kind of like barracks, but with normal beds. They're only used for sleeping. Instead they have separate private rooms for changing, personal time, and keeping their personal affects.