idiom · to exaggerate or add sensational details to a story or narration, often to make it more interesting or to mislead

他在叙述这件事时故意添油加醋，把责任全都推到了别人身上。

expression · literally to add oil and vinegar to food or a dish as seasoning

他在做凉拌菜时添油加醋，调出的味道非常鲜美。