[Rosen hadn't really expected him to but the corner of his mouth quirks upward when Lance plays along with the joke.]

That was the first thing Sans ever said to me here.

[Admittedly someone attempting to play a prank on you is an odd thing to be nostalgic about, but Lee feels an uncomfortable yet familiar tightness in his chest thinking about it. He knows what the sadness of loss feel like when it rears its head in his life]