Why do you think Inuyasha is always sleeping sitting upright? I've never seen him snuggle into a futon for sleep. He hardly ever lays down for sleeping. The only time i've seen him do it is at kagome's house or when he's injured. Also he never uses blankets??? like at kagomes house he never bothered with a blanket. I've just been thinking his sleeping habits are just odd.

Because sleeping means vulnerability. The more comfortable you are, the deeper you fall into unconsciousness and the more defenseless you become.

To Inuyasha, truly relaxing was never an option because his enemies could take advantage of his fragil state and attack him, so he constantly has to keep his guard up.

He needs to make sure that he is always ready to fight or flee, because his very survival depends on it and a slip up can be fatal. 

And even though the rest of the gang are skilled fighters as well, it’s safe to say Inuyasha took upon himself to watch over them as an (un)official guardian or protector.

It’s not just his life on the line anymore. And this is a great responsibility.

But even his supernatural body has its limits and we watched Inuyasha surrender to them in a few occasions. 

Granted, he was still sitting on this one, but he is visibly more relaxed. And, of course:

Something that catches my attention is how peaceful his expression is in both moments and how much it reminds me of the time he was sealed.

If not more, I’d dare to say they are at least on the same level of serenity as of when he was dead to the world, without a single thing to worry about. 

It’s also important to notice that two of these scenes have something in common: his placid sleeping was catalyzed by Kagome’s presence.

And there is a very good explanation for that:

Kagome has such a grip on him that her presence or even just her smell surrounding him is enough to put his mind at easy. And I like to think this happened for two reasons.

One, Inuyasha associated Kagome with a safe place. With Kagome, he finds comfort, acceptance, peace. He associated her with home and that’s how he manages to be so carefree when he is with her.

Two, Inuyasha trusts Kagome with his life. Literally and figuratively speaking. He knows he can count on her not to hurt him in his most vulnerable state and he also trusts her to watch over him and have his back if needed because even though it’s usually the other way around, with Inuyasha protecting her, their relationship is based on reciprocity. And he came to learn how much he means to her and how powerful she actually is.

Finally, I have always assumed the Fire Rat kept him warm enough, since he makes a show out of putting on Kagome whenever she’s cold or sick. And because of the childhood memories attached to it, it could also work as a security blanket of sorts, considering its main purpose is to protect the owner.

BONUS: he holds to Tessaiga as the weapon it is in any other circumstances, but he clings to it like it’s a teddy bear when he’s sleeping in Kagome’s bed. And I, for one, just think it’s the sweetest thing ever.