As Black: Kingside

Let's change colour — see how you hold up as Black. The rule is mirrored: Black's kingside castling brings the king to g8, the rook to f8. The eighth rank is your first, and the final squares are the same, just with an eight instead of a one. Whoever fumbles the coordinates as Black loses seconds on the clock — and I don't forgive seconds. King e8 — onto the rook h8.