...he has said it a lot, hasn't he? It's probably all white noise to Frisk, by now. It's hard for a skeletal dragon to look sheepish, but Sans manages it. And when Frisk lays down, he shifts until he's curled just a bit around them. In a way that hopefully indicates that pressing against him would not be a problem - he's not good for much else, at this point, and everyone knows that skeletons are very soft and cuddly. Like this, his tail is close enough to their shoe that Frisk might see it wag a bit at that correction. He doesn't particularly want to be left alone right now, either, but neither is he terribly good company.

"...want a ride?" he asks, only half joking.