Literally “add oil, add vinegar” — the same image English uses with “to spice things up”. Cooking-as-storytelling: oil and vinegar make the dish (the tale) more flavorful than the plain truth.
usage
Variant form of the more common 添油加醋 (tiānyóujiācù) — same meaning, characters reshuffled. Often slightly disapproving: the speaker thinks the embellishment distorts the truth.
