Y/n
You've rather excited.

"So where in my room do you want your space?"

He looks at you confused.

"your room?"

You kinda feel like facepalming right now, but you refrain.

"Yeah...um you see...
IlivewithotherpeopleandIdon'tknowhowtheywouldreacttoyouandIdon'twanttoforceyoutotakearisklikethatandyoudon'thavetostayinmyroomit'sjusteasierformetofindyouandi'dmakesureyou'dhaveprivacyanditssaferthananywhereelseandIfIleaveyouwouldbeabletoaccessandusemyphonesinceitsaflipphoneandbeabletocontactmebytextingmyemailandmyroomhasgoodhidingplacesincasesomeoneelsecomesinbutyoudon'thavetostayinhereIwon'tforceyouto.."

Sigh..you and your nervous illegible ranting..

"Oh, sorry I didn't mean it that way..I've never been allowed to sleep in a persons room before. I'm used to just taking what I can get and not complaining too much. I guess if your ok with it I'm fine with staying in your room, plus considering all that you said It'd probably be better if I stayed in here."

You're pretty sure he just..
1. didn't think poorly of you or your ranting
2. attempted to calm your nerves
and 3. actually opened up to you a bit...
he probably would have been effective at calming you down if you had not just gotten ecstatic over the fact that he opened up even a little.
He looks around the room, and seems to take a liking to the top of your nightstand.

"um can I stay there?"

He points to your nightstand.

"Yeah sure! I can arrange that!"

You're rather happy about his choice.
But before you set anything up you first need to take care of sans.

"But first you're going to need a bath, or a shower, whichever you prefer, and your clothes need to be washed...it's a good thing I have a lot of hand towels..."

He looks at himself and agrees with you, and starts stripping.
You blushed intensely, he doesn't notice.
Before he could take off anything else you stop him.

"before you completely strip in front of me...let me just go grab you a towel to ya know keep your privacy, private."

You take off towards the laundry room to go grab a hand towel.

Smol sans
Huh.
That's..different..
Im not exactly used to..privacy I guess..
I was treated like a doll for most of my life..
So I've grown used to having to strip in front of others..
The first time I was embarrassed, but over time it was just became normal thing..
1. You gave me back my privacy
2. You treated me respectfully
And 3. you gave me the option to choose
I like this and I think I'm starting to like you as a person..
I sit patiently atop a pillow on your bed waiting for you to come back with the towel.
You eventually come back holding a small cyan colored towel and hand it to me.

"Um...here..wait! Did you want a bath or a shower?"

I take the towel from you and wrap it around myself.

"Well um..I've already been showered in kindness..so i'll go with the bath..." ;3

You seem to have noticed the pun/complement, and I catch you slightly blushing.
Cute..

"ok! Before I set it up is there anything specific you need for it, or in general?"

I don't really get what you meant by that last part of your response.
I guess I'll just respond to the first part of it then..

"Soap?"

You smile at this for some reason, I don't exactly get why though..
You go over to your desk and grab a pad and pencil and start jotting things down.

"Ok what water temperature?"

Are you just gonna jot down all the answers I give you?
...
Are you trying to set up the perfect bath for me or something?
Well..maybe you're just nice like that?
I might as well just answer, it's not like anything bad will happen..

"Warm.."

Like I thought, you write something on your pad.
Most likely it's my answer.

"Ok...anything you want?"

Wait what? I don't-understand..
What do you even mean by that?
Well, I guess I might as well just ask you.
It's not like I'm going to get the answer by any other means.

"what do you mean?"

She appears to be struck with some sort of realization, and makes an 'oooh I get it' kind of expression..
I'm still confused..

"Well, I want you to be as comfortable as possible! So if you want anything i will try to get it for you! As long as it's within reason..."

Wait what?! Seriously?!
I am shook.
No one has ever done anything like that for me, ever.
Neither have those words ever been spoken to me in that order.
I don't really know what to do with this..
but I might as well attempt to say something,

"Uh..."

You stare at me expectantly..
What the f*ck do I say next?!

"you don't have to respond right now if you're not ready..."

You must've notice the panicked expression on my face..
Welp, that's a relief...

"Ok"

Y/n
"I'll go get your bath set up ok!"

You leave to grab a small bowl, fill it with warm water, grab a small bar of soap, and hand it to Smol sans.
A realization of previous occurrences finally hits you.
You almost saw sans naked...
Cue *internal fan girl screaming*
Well smol sans, but still..
Wait..but he is just a skeleton though..
You set the 'bath' down near him and grab his Smol clothes to go get them washed.
You then desperately search for something he can wear while his clothes are washing.
You eventually find a Navy blue sleeveless doll hoodie, and blue doll jeans.
They probably won't exactly fit him perfectly but at least it's something.
After Smol sans was finally done, and called you over, you handed him the clothes for him to change into and looked away while he put them on.
Once he finished changing, you almost choked after seeing how he looked.
He looked kinda hot..for a smol sans that is..
But anyways, you think it's a good look for him.
Maybe too good..but let's not focus on that for right now..

You proceed to ask him a few questions about how he wants his space to look and what he wants to have. And the finished product is absolutely (whatever it is).
*insert finished product*

After that, you set him in his space and decided to take a food break.

"Hey, i'm going to grab a snack do you want anything?"

You hear his stomach lightly grumble..what coincidental timing..

"Yeah um...do you have ketchup?"

You're happy that even the Smol version of sans likes ketchup, and that you have it.

"Um yeah! I can get that for you!"

You start to leave, but stop as soon as Smol sans starts to ask you something,

"hey...mama?"

You halt immediately.

"Please don't call me that. I know that's what bitties call their owners, but I don't want to be your owner...I want to be your friend. So you can just call me by my name."

You hope he doesn't take it the wrong way..

"...ok...but, I don't know your name..."

Sigh..your glad he is ok with it.
However, you facepalm once you realized you never told him your name.

"I'm sorry! I'm bad at introductions...My name is y/n!"

You can't believe you forgot to tell him your name of all things.

"it's fine, I never told you my name either, it's Sansy by the way."

Huh I thought it would be the same...

"So it's not just sans?"

He seems confused..you wonder why.

"Wait how do you-"

Now realizing why he was confused, you cut him off.

"Oh, I knew about Undertale and bitties, I just didn't know they existed in real life..."

You wonder how he didn't realize this before.

"Oh, I probably should've realized that sooner..."

Yeah..I mean who in there right mind would just let someone who is homeless and trespassing on their property live with them, if they didn't already know a decent amount about the person?
He's kinda lucky you're a fangirl, and can't really say no to him..

"It's fine, i'll go grab that food now...be right back!"

You leave to go and grab the food.