Safety
"So is there something wrong with your bed?"
"Mh?"
"Well I'd rather rule out external issues before delving into possible diagnoses."
"What are you on about, John."
"You've been kipping on the sofa every day. Either this is where you sleep now, likely because your bed is a biohazard area, or there's something causing extreme exhaustion and I should be worried about you. I'd rather not be worried about you."
"Hmh. Compassionate."
"Mm. And?"
"No, there is nothing wrong with my bed, however yes, this does seem to have become my designated sleeping area. Nothing to worry about, Doctor."
"Right. I find it hard to believe that our ratty old sofa -"
"It's a fine sofa."
"- is more comfortable than your massive plush bed."
"It's a fine sofa, John."
"It's fine for sitting on."
"And I've been enjoying -
"Ha!"
"- sleeping on it as well."
"Now I highly doubt that, Sherlock. What's wrong with your bed?"
"Nothing."
"You just refuse to sleep in it for no reason, then?"
"... It's a fine sofa."
"... Alright, fine, ok. Christ. Just don't come whinging to me when you can't stand up straight anymore because your back's in a horrible knot."
"I won't."
"Fine."
"Fine."
"Sherlock, I'm back. And yes, I've been gone. Five days. I did tell you...Christ, you look like shit, what happened?"
"Ah, John. You're back. Good. Finally."
"...Sher?"
Sherlock hasn't slept much in the past five days. Now, with John home, he can get on with it. He shifts from his position seated on the sofa, to lie stretched across it now, one arm over his eyes, the other across his belly. He's asleep before John can come from the doorway to stand beside him.
John won't intentionally wake him. Clearly the sleep is much-needed. However, John is incredibly worried about his friend, and so he kneels carefully beside the sofa and begins a rudimentary check-up. Sherlock only wakes up enough to bat at John's prodding hand, and then to snag it and hold it to his own chest. Trapped like that, John settles back on his heels to consider the detective for a few moments, before finally he gently extracts his hand and goes about settling in again after a week away for a medical conference.
"... You've built a nest in my room."
"Yes."
"Why?"
"So you can sleep in your bed."
"...?"
"You can't sleep alone."
"John."
"Look, Sherlock. I've been keeping an eye on you since I came back from that conference last month. You only sleep when I'm around. Now I don't want to dive too deep into whether just anyone would do or if there's something specific about me, but the fact is, you choose to sleep where you can know there's someone near...Do you not feel safe at night, Sherlock?"
"..."
"...Are you -...afraid of the dark? It's fine if you -"
"No."
"Right, ok. You just don't feel safe on your own?"
"..."
"...Well. Regardless of why, you sleep while I'm around. You need to sleep in a bed. Therefore, I'll be around your bed."
"You don't want me hurting myself sleeping on the sofa so you'll hurt yourself sleeping on the floor?"
"Well, we're hardly going to fit a second bed in here, unless you downgrade yours and I highly doubt -
"Mine's big enough."
"...?"
"You said, it's massive."
"Did I?"
"When you first questioned me about sleeping on the sofa."
"...Oh, right."
"It is big enough for two."
"I - Yes. It is."
"But."
"Sherlock, I. I mean I've shared sleeping spaces with plenty of people before but."
"You don't have to be gay to sleep beside someone."
"No of course Sherlock I know that, but you don't exactly seem the cuddling sort."
"And you are?"
"No - God's sake. Just. Sharing a bed is intimate, sex or no. You strike me as completely uninterested in such a thing."
"And yet I've been sleeping on a sofa while you occupy the sitting room."
"I - Yes but that's hardly the same."
"John."
"And what if I have a nightmare and hurt you?"
"John."
"..."
"Just. Lie down."
"...Right. Fine. Alright. As long as you're sure."
"It's only sleeping, stop being so ridiculous."
...
"...Thank you, John."
"Ah -...Yeah. You're welcome."
In the morning John wakes tangled up in long limbs. Sherlock never did deny being a cuddler.