(G/K) C - Conservative - Something that shouldn't offend anyone's grandma.
(PG/K+) S - Suggestive - Uses moderate language, suggests violence or adult situations, but doesn't describe them.
(PG-13/T) B - Brazen - Uses strong language, includes moderate violence or mature sexual themes, but no graphic violence or graphic sexual descriptions.
(R/M) W - Wanton - Descriptions of graphic violence or graphic sexual descriptions.
(NC-17/MA) L - Lascivious - Explicit, lewd or deviant sexual descriptions.
From sycophanthex.com/. Used with permission.