Play the 4 chord, then flat its third before resolving home. That one chromatic slip (the b6 of the key) is instant bittersweet — the most-loved borrowed chord in pop.
hear it in “Creep” (Radiohead) — the final 4 → 4-
Lead-in — how players set it upA bright 1 → 4 lift sets the trap the 4- springs.Or approach 4 from 2-⁷ — predominants stack politely.From 1⁷ for the full gospel walk into the borrowed color.Follow — where it usually goesResolve to 1, or detour 4- → b7⁷ for the backdoor.Route 4- through the backdoor instead of straight home.Or land on 1Δ7 and let 3-⁷ carry the bittersweet on.
Hold the key's 1 over the 4- (it's that chord's 5th) while the b6 aches beneath — one still note, moving world.Target tones (in C)F — lean on A (3)Fm — lean on Ab (b3)C — lean on E (3)Half-step wiresA ↘ Ab · F ↘ E · Ab ↘ G