"He in the city or anything?" Unperturbed by Rin's reaction - or possibly enjoying it just a little too much, can you blame him? - Sans crumples up the empty wrapper and shoves it into his pocket.

Yeah, he wasn't super hungry, but it was worth the sight gag and the reaction he got from it, so sue him. Actually don't sue him, though, he's got absolutely nothing to his name but a couple packs of ketchup and a great poker face.