Three's a Crowd
They couldn't very well request a third futon when there's technically only two of them, so that night, Nezuko dozed in what was supposed to be his futon and Tanjirou was left to share with an all-too amused Shinobu-san.
He isn't particularly worried about keeping his hands to himself, but rather at the impropriety of it. They weren't even married yet! Tanjirou scooted as far as he could, but Shinobu-san wasn't having any of it, pulling him back and pillowing her head on his shoulder.
"Just hold me and sleep, Tanjirou," she sighs, perfectly comfortable. So that's what he does.
