"Uh," Sans says, not very helpfully, his eyebrows raised. He puts a skeleton hand on Greg's shoulder in a manner that is totally comforting and not at all trying to creep him out. "Not anymore than you can 'turn off' being good at sports, pal. Magic is a muscle. Or should I say, music is a muscle? The more you work it the stronger it gets."

It's said with a weird amount of authority for someone who only technically became aware of magic a couple months ago, but Sans is apparently a time science wizard in a past life, so maybe he really is the expert on these things.