[Endearing was the word that came to mind, and Sans leans forward too, jaw cupped in bony hand as he mirrored the guys thoughtful pose.]

Guess it wouldn't do you much good if you didn't know between the lie and the guesses, huh? Alright, here goes, pal...

[He holds up a finger, looping it through the air with flourish before landing it against Lucio's nose. Boop.]

Here's your hint: these circles need to be turned just so t'get through here. [He never said it'd be a good hint.] My guess is that it can't be accomplished with just one person. As for an inkling, pretty sure if this one's like that, most of 'em will be coop levels.

N' I'm happy to help out pal. [A final boop, and Sans withdraws again, leaning back against the wall.] No extra charge.

[There's your lie for ya.]