15: Singing headcanon.
I think Sans would be a surprisingly good singer, but he’d be too shy to actually sing in front of anyone. His voice would be rather low and quiet, something like Corey Taylor (The Stone Sour Corey Taylor, not the Slipknot Corey Taylor XD)
17: Soft spot headcanon:
Now I’m not sure what ‘soft spot’ means in this context, so I’ll give two for the price of one 😀
In terms of who he would have a soft spot for, he’d def have one for Alphys. I headcanon (hey, make that three lol) that they’ve been friends since they were young, so they’re like brother and sister. When Sans knows of some of the stuff she did, he’s not happy, but he doesn’t give her a hard time.
In terms of like, spots he would like to be ‘pet’…then I’d say his head, his neck ad his ribs (but especially his neck >:D)
18: Favourite possession headcanon:
Hm…I think he’d value his jacket, ‘cause I feel like Papyrus gave it to him. Also, any sock. He loves his socks.