Teach something you know to someone younger. That’s the closest thing to living forever.

Knowledge is the part of you that can move into another person intact. It does not decay in storage the way objects do, and once somebody else holds it properly, it stops depending on you at all. That transfer is a real form of continuation rather than a figure of speech.

Do not wait until you have mastered the thing. Explain what you already understand to somebody a step behind, slowly enough to be useful. Writing it down works too, since a clear explanation keeps working when you are not in the room.