[This is one of many things Sans doesn't really want to talk about. But he has to now.] No. Nobody's mentioned it, anyway. I guess someone might notice that I'm acting different, if it was a really big emotion, but they can't feel the magic. [But doing it on purpose means he'd be expecting it, so he could get it more under control. Which, yes, does mean Sans could be doing it all the time secretly, except Sans really doesn't want to do that.]
no subject