Idk how to explain this but!
(Your choice of) skeleboys with an s/o who used to have a habit of laughing so hard that they could nearly stand at even the slightest funny thing..but they kind of lost that due to a rough patch in their life so they haven’t been doing it at all. Then recently, as they’re getting better, they say something funny while they’re..in the kitchen? Out for a walk? Something like that! And the s/o just LOSES their mind, like one of the happiest and genuine laughs they had in a long time. How would they react?
Sans: If you asked what Sans’ favorite passtime was, and if he gave you an honest answer...it would be making people laugh. There’s just something about making even the most stone-faced person giggle that leaves his chest feeling a little lighter. So when he hears the laughter bubble up from deep within your chest and that twinkle finds itself glittering in your eyes, he knows he’s done right. And he finds himself beaming as he laughs along with you to something that wasn’t even meant to be that funny.
Red: Now, Red dosn’t think himself to be the funniest guy around...especially after meeting his alternate selves, but when he does make someone laugh he can’t help but feel a bit smug about it. Like yeah, take that world. He’s made someone happy even if things are totally suckish. So when he hears you laugh for the first time in a while? His soul is FLYING. His grin is sharklike and he starts laughing with you and roughly pulls you to his chest, telling you you’re a dork and it wasn’t even that funny.
Bear: Bear shed a tear the first time he made someone laugh in this alternate timeline. He’d almost forgotton how good it felt to make someone laugh. So when it does happen he finds himself getting giddy. He can’t help it. The small infectious joy of laughter makes him feel just like he did all those years before everything went wrong in the underground. And the fact that it’s YOU he accidentally made laugh? Knowing you’ve been having a hard time? Bear can’t help but scoop you up in his arms and press his forehead to yours as you both laugh together.